Moths of Australia

By IFB Common

This is the first comprehensive, reliable, well-illustrated book covering the enormous diversity of Australian moths, summarising our knowledge of them by the acknowledged experts in the field.

The text includes nomenclature and a wealth of information on distribution, larval food plants, and the fascinating behaviour of these often colourful insects. There are authoritative accounts of moth structure, their life history, biology, population control, economic significance, evolution and geographical distribution.

Additional features include a section on collecting and studying moths, a glossary, a detailed index and an extensive list of references.

• Language: English
• Publisher: CSIRO PUBLISHING
• Release date: Jan 1, 1990
• ISBN: 9780643102712

Book preview

PART ONE

MOTHS

AND THEIR

ENVIRONMENT

1

STRUCTURE AND LIFE HISTORY

EGG

Moth eggs vary enormously in size, shape and surface ornamentation depending on the family to which they belong. The shell or chorion of the egg may be smooth or carry reticulated patterns of raised ridges, or longitudinal ribs often with finer cross ribbing, and occasionally other projections. The micropyle, through which the sperm enters the eggjust before it is laid, is usually surrounded by a radiating, rosette-like pattern of reticulated ridges.

The position of the micropyle in relation to the general shape of the egg when deposited on a horizontal sur face distinguishes two main types of moth eggs (Figs 1-3). If the egg is asymmetrical in horizontal section and the micropylar axis is horizontal, with the micropyle at one end, it is known as a flat egg. If the egg is symmetrical in horizontal section, and the micropylar axis is vertical, with the micropyle at the top, it is known as an upright egg. In general, flat eggs are characteristic of the more primitive groups of moths, while the more advanced or specialized groups usually have upright eggs. Flat eggs may be more or less oval or cylindrical in shape, or flattened to various degrees, some being almost like fish scales. Upright eggs may be nearly spherical with one slightly flattened surface by which they are attached to a leaf or other object, or they may be hemispherical or subcylindrical and attached by a flat base.

Moth eggs may be laid singly or in groups of various numbers, usually on or near the food plant of the larva, but some species of Hepialidae drop their eggs, apparently at random, while the moth is in flight. Usually each egg is glued to the substrate by a secretion of the female accessory glands, applied after fertilization to the chorion as the egg passes down the genital tract. Sometimes after each batch of eggs is laid it is covered by a film of accessory-gland secretion, and occasionally special scales from the female’s body or wings may be attached to the secretion. In some groups in the Limacodidae, Pyralidae and Noctuoidea, the whole batch of eggs is densely covered by, or mixed with, a mass of special scales from the tip of the female’s abdomen. In Isotenes and Cryptoptila (Tortricidae) the female glues special scales vertically around the margin of her egg batch; in Isotenes these scales form a dense mass at the end of her abdomen, while in Cryptoptila they are located in a pouch on the costa of the hind wing.

Fig. 1. Types of moth eggs: 1,2, Flat eggs of Digglesia rufescens (Lasiocampidae) and Isotenes miserana (Tortricidae); 3,4, Upright eggs of Nyctemera amica (Arctiidae) and Cosmodes elegans (Noctuidae). Scales = 0.5 mm.

Fig. 2. Moth eggs: 1, Eulechria clytophanes, 2, Cryptophasa rubescens (Oecophoridae); 3, Cophomantella lychnocentra. 4, Crocanthes prasinopis (Lecithoceridae); 5,6, Cyc!otorna sp. (Cyclotornidae); 7, Aglaopus pyrrhata (Thyrididae); 8, Culama sp. (Cossidae); 9, Oenochroma vinaria, 10, Aeolochroma metarhodata, 11, Epidesmia chilonaria, 12, Anisozyga pieroides, 13, Prasinocyma rhodocosma (Geometridae). Scales = 0.1 mm.

Fig. 3. Moth eggs: 1, Acropteris nanula (Uraniidae); 2, Agape chloropyga, 3, Digama marmorea (Aganaidae); 4, Neola semiaurata, 5, Sorama bicolor (Notodontidae); 6, Discophlebia catocalina, 7, Trichiocercus sparshalli (Thaumetopoeidae); 8,11, Leptocneria reducta (Lyrnantriidae); 9, Uraba metallopa, 12, Earias perhuegeli (Noctuidae); 10, Amsacta marginata (Arctiidae). Scales 1-6,8-12 = 0.1 mm, 7 = 1.0 mm.

The incubation period for moth eggs is extremely variable, often depending on temperature but sometimes on the physiological condition of the female when the eggs are laid. Frequently the eggs hatch within a few days of oviposition but, if a diapause should intervene, hatching may be delayed for several months. The young moth larva normally bites its way out of the egg by means of its strong mandibles and, after hatching, some species devour the remains of the egg shell before attacking their normal food. In the Hepialoidea and Mnesarchaeoidea (Exoporia), however, the egg splits open to allow the escape of the larva.

LARVA

The moth larva or caterpillar must devour sufficient food during its lifetime to carry it through the non-feeding pupal stage and produce the fully functional adult. As its outer skin or cuticle is not elastic and does not expand during growth, the larva moults its cuticle several times. The period between two successive moults or ecdyses is called an instar. A larva that has hatched from the egg but has not yet moulted its cuticle is said to be in its first instar. Moth larvae commonly have five or six instars, but the number may range from three to many. Three main divisions of a larva may be recognized: head, thorax and abdomen.

Head

The head or cranium (Fig. 4) is a hard, rounded, sclerotized capsule with a V-shaped middorsal indentation, known as the epicranial notch or vertical triangle. The head capsule provides muscular support for the mouthparts and bears various sensory organs connected to the brain and central nervous system. It may be hypognathous, with the mouthparts directed downwards, or prognathous, with the mouthparts directed forwards. The head capsule has a large posterior opening into the thorax, the occipitalforamen, and is strengthened dorsally by an inverted Y-shaped internal thickening visible on the surface as the median and lateral adfrontal sutures (singular: suture). Early-instar larvae usually moult the head capsule intact, but in later instars, and even in the first instar of Oncopera (Hepialidae), there appear laterally from the ad frontal sutures two dorsal lines of weakness, the ecdysial lines, along which the head capsule splits at ecdysis. The space between the adfrontal sutures and the ecdysial lines is known as the adfrontal area. A triangular area between the adfrontal sutures is a more or less fused frons and clypeus called the frontoclypeus, which is bordered in front by the anteclypeus with which the labrum articulates. Strong dentate mandibles occur in most forms, but in sap-feeding leaf-miners the mandibles are drastically modified (Fig. 72.5). The maxillae carry a pair of usually 3-segmented maxillary palpi and the labium usually carries a spinneret on the prementum and a pair of usually 2-segmented labial palpi. Lateral from the anterior ends of the adfrontal sutures are the antennae, which are usually 3-segmented. On each side of the head capsule there is a group of up to 6, or rarely 7 (Heterobathmiina), stemmata (incorrectly called ocelli), which are single-lens visual organs. The head also bears a series of sensory setae and punctures or pores.

Fig. 4. Larva: 1,2. Head of Hyalobathra (Pyralidae), dorsal and lateral, showing setae.

Thorax

The larval thorax (Fig. 5.1) is divided into three segments, the pro-, meso- and metathorax, each of which usually bears a pair of true legs. The thoracic legs normally have five segments and a single terminal claw, but they may be modified in various ways, may have a reduced number of segments, or may be absent. The prothorax carries a middorsal sclerotized area, the prothoracic shield or plate, and a series of sensory setae and punctures. The other two thoracic segments also bear series of sensory setae. In most larval Lepidoptera there is a pair of lateral spiracles on the prothorax, but the early instars of some aquatic Pyralidae, and all instars of Acentropus (Pyralidae) are without thoracic spiracles. In Micropterix (Zeugloptera) there is a pair of functional spiracles on the metathorax also; these are present but non -functional in Heterobathmia (Heterobathmiina). Some species of Noctuoidea have eversible glandular organs on the prothorax beneath the head, which may secrete formic acid used to defend the larva against predators (see p.37).

Fig. 5. Larvae: 1, Hyalobathra (Pyralidae), lateral, abdominal segments 3-5 omitted; 2, Setal map of Philobota (Oecophoridae).

Abdomen

Abdomen The abdomen (Fig. 5.1) consists of ten segments with series of sensory setae and sometimes glandular organs. In the larvae of most moths there are paired lateral spiracles on abdominal segments 1 to 8, but in Micropterix (Zeugloptera) they are lacking on segment 8, and in aquatic Pyralidae they may be restricted to segments 1 to 3 or may be absent altogether. Ventralleg-like organs, the ventral prolegs (Fig. 6.14), are usually present on segments 3 to 6, but in the exotic families Megalopygidae and Dalceridae there are paired ventral prolegs on segments 2 to 7, and in the last two instars of Dalceridae all the prolegs bear crochets (see below) (Stehr and McFarland 1987). On segment 10 there is usually a pair of anal prolegs or anal claspers. Dorsally on segment 10 there is also a sclerotized plate, the anal shield or plate. In some Gelechiidae and Tortricidae the tenth segment also carries a sclerotized fork or comb (Fig. 6.13) above the anus, used to eject faecal pellets, and in some Zygaenidae similar forked structures are present above and on each side of the anus. The prolegs may sometimes be modified or reduced in number and, especially in leaf-mining larvae, may be lost altogether. The flattened end of each proleg formsthe planta, which usually carries a series of small sclerotized hooks or crochets. The presence, number and arrangement of the crochets (Fig. 6) provides information of taxonomic value. When they are all of one length the crochets are said to be uniordinal, of two or three lengths biordinal or triordinal, and of many lengths multiordinal. Sometimes the crochets are in two or more roughly concentric circles or rows and are then called biserial or multiserial. In more primitive larvaethey are usually arranged in a complete or almost complete circle but are sometimes in one or two transverse bands, whereas in larvae of advanced groups they are usually arranged in a longitudinal row known as a mesoseries.

Fig. 6. Larvae: 1-11, Arrangements of crochets: 1,2, uniordinal and biordinal circles; 3,4, paired, uniordinal, transverse bands; 5, biordinal transverse ellipse (Xyleutes); 6, uniordinal transverse bands (Heliozela); 7, multiserial circle (Yponomeuta); 8, uniordinal, mesal penellipse; 9, biordinal lateral penellipse; 10, uniordinal heteroideous mesoseries (many Arctiidae); 11, uniordinal homoideous mesoseries (most Noctuidae). 12, Thoracic leg. 13, Anal fork or comb (Tortricidae). 14, Ventral proleg (Plutella). 15, Pinaculum with two plumose setae. 16. Verruca. 17, Scolus (Opodiphtherai.

In some species in which the larvae have a relatively transparent cuticle, paired gonads may be visible mid dorsally on abdominal segments 5 or 6 in males. The sexes of larvae in certain species can be determined by the presence in females of a pair of ventral pits on abdominal segments 8 and 9, whereas in males there is only a single ventral pit on segment 9.

The occurrence and distribution of the setae and punctures of the larval head, thorax and abdomen are of major taxonomic significance. Those present in the first-instar larva are known as primary setae and punctures, but additional subprimary and secondary setae are often acquired in the second or later instars. Hair-like and often dense secondary setae are found especially in those families with larvae that feed fully exposed. Primary and subprimary setae have a characteristic arrangement and have received special names. They occur singly or in groups, often on sclerotized plates called pinacula (singular: pinaculum). A more or less conical pinaculum bearing one or more setae is called a chalaza. Secondary setae may be distributed generally over the surface or be arranged in various tufts or pencils, or they may be grouped on sclerotized plates or on a variety of protuberances (Fig. 6). They may be simple, without branches, or plumose, with numerous fine branches. A group of radiating, simple or plumose setae arranged on a slightly raised plate is called a verruca. Verrucae may occupy the positions of primary setae and, like the pinacula on which they occur, may sometimes fuse with other adjacent verrucae. Smooth or irregular elevated protuberances bearing setae are known as scoli (singular: scolus). The presence of secondary setae usually makes the identification of the primary or subprimary setae very difficult or impossible.

Chaetotaxy

The arrangement of the setae and punctures in larvae is known as the chaetotaxy, and is depicted diagrammatically in setal maps (Fig. 5.2). It should be remembered that the larvae of relatively few moths have been studied in detail and, therefore, there may be exceptions to the following outline of larval chaetotaxy.

The principal primary and sub primary setae and punctures of the larval head (Fig. 4) are grouped in ten sets. There are two pairs of ad frontal setae (AF1 and AF2), situated in the ad frontal area and associated with a pair of adfrontal punctures (AFa). A pair of frontal setae (F1) and a pair of frontal punctures (Fa) are present on the frontoclypeus, and near its anterior margin there are two pairs of clypeal setae (C1 and C2). The anterior setae (A1-A3) and an anterior puncture (Aa) are situated between the ad frontal area and the stemmata, and behind them are two posterior setae (P 1 and P2) and two posterior punctures (Pa and Pb). Further back and more or less in a longitudinal row are three small setae (V1-V3) and a puncture (Va). Associated with the stemmata are three stemmatal setae (Sl-S3) and a stemmatal puncture Sa, and beneath them three substemmatal setae (SS1-SS3) and a puncture (SSa). Posterior to the stemmata, and often more dorsal, is a lateral seta (L1) and a lateral puncture (La). Posterior to the stemmata, and usually more ventral, there is usually one genal seta (G1) and a genal puncture (Ga), but in a few families, such as Hepialidae, there are two genal setae (G1 and G2). Puncture Ga is absent in Hepialidae. The length of the cranial setae varies greatly from group to group, but the more anterior setae are usually long and are tactile in function. In those larvae with prognathous heads, in which the head capsule is often partially withdrawn into the prothorax, the more posterior setae, especially V1 to V3 and G1, are usually very short indeed. It is probable that these very short setae function as proprioceptors, informing the larva of its own head movements.

The primary and subprimary setae of the thorax and abdomen are of two kinds, the long and usually tactile setae and the minute or proprioceptor setae. On the prothoracic shield there are six primary tactile setae, two of which (XOI and X02) do not occur on the other segments. The other four, the two dorsal setae (D1 and D2) and the two subdorsal setae (SD1 and SD2) are also present on the meso- and metathorax and on abdominal segments 1 to 8 (A1 to A8), and D1 and D2 also occur on A9 and AIO. SD1 is present on A9 and is usually a very long seta, but SD2 is always absent on this segment. On A1 to A8, SD2 is almost invariably a minute seta and can be easily overlooked.

Below the subdorsal setae are two or three lateral setae (L1 to L3). L1 and L2 are primary setae on the prothorax and on the first eight abdominal segments, and are always present in first-instar larvae. On the meso- and meta-thorax, L1 is primary whereas L2 and L3 are subprimary, appearing only in the second and later instars. L3 is a subprimary seta on the prothorax and on A1 to A8, but is absent from the prothorax in all instars of Copromorphoidea, Alucitoidea, Hyblaeoidea, Thyridoidea, Pyraloidea, and the more advanced superfamilies. L1 is apparently always present on A9, but other lateral setae may be present or absent on this segment.

Up to three primary, subventral setae (SVI to SV3) may occur below the lateral setae, but never more than two (SVI and SV2) are present in the first-instar larvae of most groups. Two primary subventral setae always occur on the prothorax of the first instar. The number of subventral setae on the meso- and meta-thorax is the same and may be either one or two. On A3 to A6 there are always two subventral setae in the first instar and three or more in later instars. However, the number of SV setae on A1 and A2 and on A7 to A9 varies from one to three or more.

Near the midventral line of all the thoracic and abdominal segments there is a single ventral seta (V I). In some families it may be located on the coxa of the thoracic legs or on the inner side of the abdominal prolegs.

Near the posterior margin of the prothorax and near the anterior margin of the thoracic segments and the first nine abdominal segments are a few minute primary setae known as microscopic or proprioceptor setae. The prothorax usually has a single posterior one (MXD 1) behind the prothoracic plate, and a ventral pair (MV2 and MV3) in front of the leg. The meso- and metathorax each have six near the anterior margin, three subdorsally (MD1, MSD1 and MSD2) and three subventrally (MV1 to MV3). In the Noctuoidea an additional subdorsal microscopic seta occurs on the metathorax. The first nine abdominal segments have a single subdorsal seta (MD1) and a single sub ventral seta (MV3), but in Notodontidae an additional subdorsal seta (MD2) may be present.

Internal anatomy

The intestinal tract in moth larvae is a relatively simple tube consisting of a short oesophagus and foregut, a much larger midgut where the food is digested, and a short hindgut and rectum. Unlike most adult moths the larval foregut is without diverticula, except in the genus Myrascia (Oecophoridae) the larvae of which have a foregut diverticulum in which oil extracted from the food is stored and used to defend the larva (see p. 37). Paired Malpighian tubules, which open near the junction of the mid- and hindgut, extract unwanted products of metabolism from the blood and discharge them into the gut for excretion.

A pair of long silk glands, which represent the salivary glands of other insects, ramify through the body and lead to the spinneret. Paired mandibular glands, opening on the inner surface of the mandibles, function as salivary glands.

The central nervous system consists of a small brain, within the head capsule, connected to a series of nerve ganglia in the thorax and abdomen. Closely associated with the nervous system are the endocrine organs, corpora cardiaca and corpora allata. Hormones responsible for regulating growth, maturation, metabolism and behaviour are released into the blood (haemolymph) by the central nervous system and the endocrine organs.

Respiration is provided by the lateral spiracles, through which air diffuses and is conveyed to the blood and internal organs by a network of tracheae. The aquatic larvae of Nymphulinae (Pyralidae) and a few Arctiidae, however, do not depend upon spiracles for respiration but have lateral filament-like outgrowths of the body wall, the cuticle of whichis permeable to oxygen dissolved in the water which thus enters the blood directly. The internal organs are bathed in blood, which fills the body cavity and maintains the characteristic shape of the larva. Blood is circulated throughout the body by means of an elongate, pulsating dorsal vessel or heart, closed posteriorly and open anteriorly. It enters the organ through a series of lateral valves and is pumped forward through the anterior opening.

PUPA

The head, thorax and abdomen of the pupa (Fig. 7) can be readily distinguished, and resemble those of the adult rather than the larva. However, the appendages are each ensheathed in cuticle and, in the more advanced families, are firmly fused to each other and to the body.

The head features a pair of prominent eyes, well-defined antennae, a labrum, and often a proboscis and maxillary and labial palpi; other structures such as pilifers and mandibles, when present, are less easily distinguished. The mandibles in the most primitive (decticous) pupae are functional and are used to cut open the cocoon before adult eclosion.

The thorax is divided into three distinct segments, visible dorsally. In the more primitive families they are more or less equal in length, but in more advanced groups the mesothorax is usually the longest segment. Portions of the legs, especially the tibiae and tarsi of the fore and mid legs, as well as some tarsal segments of the hind legs, are exposed ventrally. The prominent fore wings largely conceal the hind wings. A pair of spiracles is usually visible at the junction of the pro- and mesothorax.

Fig. 7. Pupae, lateral and ventral: 1, Synanthedon tipuliformis (Sesiidae); 2, Hypobapta eugramma (Geometridae).

The pupal abdomen consists of ten segments, the last three of which are always fused together. In most pupae some of the abdominal segments are capable of movement; the more primitive the species, the greater the number of movable abdominal segments. A segment is said to be movable if movement is possible between it and the segments preceding and following it. In the pupae of some species the margins of movable segments bear small ridges or tubercles which, when rubbed together, produce stridulatory sounds (Fig. 11.8,9) (see pp. 37-8). Lateral spiracles are always present on the first seven segments of the abdomen, and often on segment 8; those on segment 1 are nearly always covered by the wings, and those on segment 8 are usually non-functional. The larval prolegs are often represented in the pupa by more or less visible vestiges on the ventral surface of the abdomen, and short straight grooves represent the anus, situated midventrally on segment 10, and the genital openings. In male pupae the genital groove usually occurs mid ventrally on segment 9, and in females of Ditrysia two, sometimes confluent, genital grooves are usually found midventrally on segments 8 and 9. Segment 10 is frequently modified in the more advanced groups to form the cremaster, which may bear a series of often hooked setae which serve to attach the pupa to the silk lining of the cocoon or, more rarely, to a pad of silk previously spun by the larva on a twig or other object. The pupal abdomen also bears setae, which represent the primary setae of the larva, but these are often minute or absent. The pupae of some families, such as the Lasiocampidae and Lymantriidae, in which the larvae are clothed in dense secondary setae, also have dense secondary setae on the pupal abdomen.

In the more primitive families, in which the pupal abdomen is highly mobile, most of the abdominal segments carry one or two dorsal transverse rows of backwardly directed spines. By wriggling its abdomen the pupa uses these to protrude itself partially from the cocoon or pupal shelter just prior to the pupal-adult ecdysis, known as eclosion. Such pupae sometimes have a sharply pointed head which helps them to rupture the silk wall of the cocoon. In the more advanced families lacking dorsal spines on the pupal abdomen, the final ecdysis occurs within the cocoon or pupal shelter and the newly emerged adult has then to escape before the wings expand (see pp.38-9).

Immediately after the final larval ecdysis most moth pupae are green in colour, but in those that are concealed in a cocoon or shelter the cuticle soon turns brown by a tanning process. Usually the cuticle of these species is relatively smooth. In a few groups, including the Pterophoridae, certain genera of the Gelechioidea, and even occasionally in Geometridae, the pupa remains fully exposed; its colour usually matches its surroundings and the cuticle often carries prominent spines, ridges, or other projections which aid camouflage.

ADULT

As in the larva and pupa, the head, thorax and abdomen are easily distinguished in the adult moth. However, some structures may be concealed by the dense covering of scales and hairs which is characteristic of all adult Lepidoptera.

Head

The head (Figs 8-11) is more or less rounded in shape and carries the mouthparts below and various sensory organs above and on the mouthparts. The vertex occupies the highest part of the head and the front is occupied by the frons. Behind the head there is a large opening, the occipital foramen, through which most of the internal organs pass to the thorax and abdomen. The head is usually clothed with overlapping, lamellar scales, but sometimes some or all of these may be piliform (hair-like), or the scales may form tufts or crests.

Fig. 8. Head and thorax, lateral, and legs of adult Amsacta marginata (Arctiidae).

The most conspicuous organs of the head are the large compound eyes and the antennae. Compound eyes are made up of numerous hexagonal facets or ommatidia, through which visual images are conveyed to the insect’s brain. As many as thirty thousand ommatidia have been recorded in the compound eye of some Sphingidae. The quality of the moth’s visual perception, however, is believed to be vastly inferior to that provided by the mammalian eye. In many species the surface of each cornea of the ommatidia is covered in minute protuberances which reduce light reflection from the cornea, thus increasing visual acuity. Short, erect, movement-detecting hairs sometimes occur between the ommatidia, and in the Hadeninae (Noctuidae) these are very numerous.

The paired, segmented antennae (Fig. 13) arise between the eyes and consist of a strong basal segment, the scape, a second segment, the pedicel, which bears a group of sensilla known as Johnston’s organ, and a multi-segmented flagellum. Although sometimes without scales, the antennae are usually partially clothed with scales and are also equipped with various sensilla, the most important of which are those used to detect odours. The scape sometimes bears an anterior pecten of stiff bristle-like scales or a dense scale-tuft. In a few groups the scape is broadly flattened and concave beneath, when it is said to form an eye-cap. The flagellum varies enormously in form, but in males its structure is usually more complex than in females. In their simplest form the antennae are said to be moniliform, when the segments are more or less ovoid in shape and the junction between successive segments is constricted. Frequently in females, and sometimes also in males, the flagellum is simple or filiform (Fig. 13.1) and bears short sensory setae or cilia. In other groups the male flagellum bears much longer cilia, or tufts of cilia, when it is said to be ciliated or fasciculate-ciliated (Fig. 13.2). Often in males, and less frequently in females, the flagellum is pectinate (Fig. 13.5,7,8), with each segment bearingone, two, three or four branches or rami (uni-, bi-, tri- or quad-ripectinate), which may in turn carry series of finer branches. Antennae with small, more or less triangular expansions of each segment are said to be dentate or serrate (Fig. 13.3), and those in which the segments are broadly flattened to form closely packed plates are said to be lamellate. In a few families the flagellum is gradually thickened towards its tip to form a ‘club’ (Fig. 13.4); in Castniidae the apical part of the flagellum is abruptly clubbed (Fig. 13.6), as in many butterflies.

Above each eye, but behind the scape, paired ocelli and chaetosemata may be pre sent or absent. The ocellus (Fig. 10.10) is a photoreceptor, but its exact functions are not fully understood. The chaetosema in its simplest form is a small tuft of radiating setae set on a slightly raised base. In some families such as the Zygaenidae (Fig. 10.9) and Uraniidae, however, the chaetosema may be large and more complex in structure, and sometimes situated at a greater distance from the eyes. The function of the chaetosema is not yet understood, but it is connected to the brain by a nerve and therefore presumably has a sensory function. In Lasiocampidae a small chaetosema-like organ occurs on the basal segment of the labial palp (Jordan 1923b).

Fig. 9. Heads of adults: 1, Sabatinca calliplaca (Micropterigidae); 2, ‘Stigmella’ sp. (Nepticulidae); 3, Opostega sp. (Opostegidae); 4, Heliozela sp. (Heliozelidae); 5, Nemophora sparsella (Adelidae); 6, Monopis icterogastra, 7, Comodica mystacinella (Tineidae); 8,9, Amphithera heteroleuca, lateral, anterior views (Roeslerstammiidae); 10, Caloptilia octopunctata (Gracillariidae); 11, Plutella xylostella (Plutellidae); 12, Yponomeuta internellus (Yponomeutidae). Scales = 0.1 mm.

Fig. 10. Heads of adults: 1, Glyphipterix sp. (Glyphipterigidae); 2, Garrha phoenopis (Oecophoridae); 3, Coleophora alcyonipennella (Coleophoridae); 4, Blastobasis tarda, (Blastobasidae); 5, Ithome lassula (Cosmopterigidae); 6, Tebenna micalis (Choreutidae); 7, Isotenes miserana (Tortricidae); 8-10, Onceropyga anelia, head, lateral, chaetosema, ocellus (Zygaenidae); 11, Imma acosma (Immidae); 12, Carposina taractis (Carposinidae). Scales 1-9,11,12 = 0.1 mm, IO = 0.01 mm.

Fig. 11. Heads of adults, 1-3: 1, Alucita phricodes(Alucitidae); 2, Hednota sp., 3, Titanoceros cataxantha, , showing large expansion of scape (Pyralidae). Ovipositors, 4-7: 4,5, Perthida glyphopa, ventral, lateral (Incurvariidae); 6, Ithome lassula, 7, Trissodoris larozona (Cosmopterigidae). 8,9, Agriophara sp., pupa, dorsum of A4, A5, showing ridges used in sound production (Stenomatinae, Oecophoridae); 10, Agape chloropyga, pupa, dorsum of mesothorax (Aganaidae); 11,12, Hypertropha tortriciformis, pupa, ventral processes of A9 (Hypertrophidae). Scales 1-3,7-11 = 0.1 mm, 4-6,12 = 0.01 mm.

Fig. 12. 1, Othreis fullonia, tip of proboscis (Noctuidae); 2, Amsacta marginata, microtymbals of metepisternum (Arctiidae); 3, Opodiphthera eucalypti, axillary spur of adult (Saturniidae); 4,5,7-9, Perthida glyphopa: 4,7, ovate primitive wing scales with sockets and aculei on wing cuticle, and details of surface of scale, 5,8, elongate normal scales, and details of surface structure of scale, 9, normal overlapping arrangement of scales (Incurvariidae); 6, Specialized pheromone-absorbing scales beneath costal fold of Cryptoptila immersana (Tortricidae). Scales 1-3,9 = 0.01 mm, 4-6 = 0.1 rnm, 7,8 = 0.001 mm.

The mouthparts of adult moths usually consist of: the labrum, with a pair of lateral pilifers each bearing a tuft of bristles; maxillae, which form the tubular proboscis or haustellum and bear a pair of segmented maxillary palpi; and the labium, which bears a pair of 2-or 3-segmented labial palpi. The most primitive suborders, Zeugloptera and Heterobathmiina, have dentate, functional mandibles which in Zeugloptera are used to crush pollen grains or fern spores upon which the adults feed. Non-dentate mandibles are present in Aglossata, but their function, if any, is not clear. Several other more primitive families retain non-functional mandibular lobes in the adult. The galeae of the maxillae are largely unmodified in the Zeugloptera, Heterobathmiina and Aglossata, but in most other moths the greatly elongated and inwardly concave galeae are joined together with interlocking hooks and spines to form the proboscis, through which liquid food or water is drawn. In most moths each half of the proboscis is provided with a nerve and muscles which enable it to be extended, and then coiled when not in use. However, in the short proboscis of Dacnonypha and Lophocoronina intrinsic muscles are absent. Several small chemoreceptive papillae are usually present near the tip of the proboscis and, in a few Noctuidae that are able to pierce the rind of fruits with the proboscis, the tip may also be armed with sharp sclerotized teeth or projections (Fig. 12.1). In some groups the proboscis is greatly reduced in size and is non-functional, and in others it may be lost altogether.

Fig. 13. Antennae: 1,2, Euchaetis metallota, , (Oecophoridae); 3, Sperchia intractana, (Tortricidae); 4, Synanthedon tipuliformis, (Sesiidae); 5, Abantiades labyrinthicus, (Hepialidae); 6, Synemon plana, (Castniidae); 7, Opodiphthera eucalypti, (Saturniidae),; 8, Xyleutes sp., (Cossidae). Scales 1-3 = 0.5 mm, 4-8 = 1 mm.

In primitive families the maxillary palpi have at most five segments and are then folded in repose beneath the head. In more advanced families the number of segments in the maxillary palp is reduced and sometimes this organ is lost completely. The labial palpi are nearly always present and usually have three segments. Near the tip of the apical segment a small, rounded, usually invaginated sensory organ (vom Rath’s organ) is present. The maxillary and labial palpi are covered with scales and in some families the base of the proboscis is also clothed with overlapping scales.

Thorax

The thorax (Fig. 8.1) of the adult moth consists of three segments, the pro-, meso- and metathorax, from each of which arise a pair of legs; the meso- and metathorax also give rise to the paired fore and hind wings. The prothorax in all moths is relatively small. In some primitive groups the metathorax is only slightly smaller than the mesothorax, but in the remainder it is much smaller. The mesothorax is universally the largest thoracic segment.

The wall of the thorax is made up of a series of sclerotized plates or sclerites connected to each other by membranes. The dorsal part of each segment is known as the notum (pro-, meso- and metanotum). At the anterior margin of the pronotum is a pair of articulated plates, the patagia, absent in Micropterigidae which have small warts on the pronotum that may represent the precursors of patagia. In the pleural membrane between the pro- and mesothorax is the anterior thoracic spiracle, whilea posterior thoracic spiracle is found in the pleural membrane between the meso- and metathorax. The mesonotum is made up of a small prescutum, a very large mesoscutum and a much smaller mesoscutellum. At the lateral margins of the mesonotum there is a pair of articulated plates, the tegulae, which cover the base of the fore wings. The metanotum has a bilobed metascutum and a smaller metascutellum. The metascutum in many groups bears lateral areas of fine microtrichia into which similar areas of microtrichia on the underside of the fore wings interlock when the moth is at rest. In Micropterigidae the axillary cord of the hind wing also has an area of microtrichia which interlocks, when the wings are folded, with an area of microtrichia on the underside of the hind wing.

The thorax is usually covered with overlapping scales, but often the thoracic scales are piliform (hair-like), especially laterally. The scales of the notum may be variously developed to form crests, and occasionally the tegulae bear very long scales, or hair-pencils may arise from lateral sclerites.

The metathorax in most Noctuoidea carries a pair of tympanal organs used for the perception of sound. Each is located in a lateral cavity with its opening directed backwards towards a similar counter-tympanal cavity at the base of the abdomen. The margin of the abdominal cavity is usually expanded laterally to form a counter-tympanal hood, which largely covers the opening of the thoracic tympanal cavity. The tympanal organ itself consists of a translucent tympanic membrane stretched across a large tracheal sac. A pair of chordotonal sensilla is connected to the middle of the tympanic membrane and leads to a thoracic ganglion. In some Arctiidae the metepisternum, a lateral sclerite in front of the tympanal organ, bears a row of minute corrugations known as microtymbals (Fig. 12.2). A muscle attached to the inner surface of this sclerite causes the microtymbals to be flexed in sequence to produce ultrasonic clicking sounds (see p. 51).

Legs The legs (Fig. 8) have five segments: coxa, trochanter, femur, tibia and tarsus. The coxa of the fore leg is movable, but in the mid and hind legs it is more or less firmly attached to the lateral sclerites of the thorax. The trochanter is always a very small segment. The tibia of the fore leg nearly always bears an epiphysis (Fig. 8.2), a variously developed articulated lobe usually provided with a marginal row of stout hairs or setae. The antennae and proboscis are cleaned by drawing them through the gap between the tibia and the comb of setae on the epiphysis. The fore tibia of the primitive Agathiphagidae also bears an apical articulating spur, absent in all other moths. The mid tibia usually carries an apical pair of spurs, and the hind tibia a median and an apical pair of similar spurs (Fig. 8.3,4). The number of tibial spurs may be reduced and, in descriptions, is represented by the formula 0-2-4 and so on. The tibiae may also bear scattered setae, regular series of setae, whorls of setae or, occasionally, apical spines, in addition to the normal covering of scales. The tibiae of males sometimes have expandable brushes or tufts of specialized scent-scales, which may fold into grooves when not in use. The tarsi are 5-segmented and are usually provided with numerous small spines and setae, as well as a pair of terminal articulated claws, a central arolium, and sometimes a pair of ventral pulvilli. The claws are curved, usually with a simple acute apex, but occasionally with an additional tooth. The fore tarsi are often provided with chemoreceptors used to recognize the presence of sugars or other materials.

Wings The wings (Fig. 14) are essentially membranous sacs with the upper and lower walls pressed closely together. A system of tubular veins provides the necessary strength. The leading or anterior margin of the outstretched wing is known as the costa; the outer margin is known as the termen; and the posterior margin is known as the dorsum or inner margin. The tip of the wing, forming the angle between the costa and the termen, is the apex, and the angle between the termen and the inner margin is the tornus. Often there is a prominent angle at the base of the costa, the humeral angle, and a similar angle near the base of the inner margin is the anal angle. In the most primitive moths the wing surface is completely or partially covered with minute hair-like microtrichia or aculei. Near the anal angle beneath the fore wing an elliptical area densely clothed with curved microtrichia is characteristic of many families. The microtrichia intermesh with those of the metascutum of the thorax when the wings are folded and ensure that the wings always assume the same position when the moth is at rest (Common 1969a). In Micropterigidae there is a similar area of microtrichia beneath the hind wing which interlock with microtrichia on the axillary cord of the hind wing when the wings are folded (Kristensen 1984b).

Fig. 14. Wing venation: 1, Aenetus ligniveren (Hepialidae), homoneurous venation; 2, Macrocyttara expressa (Cossidae), heteroneurous venation.

The upper and lower wing membranes are usually densely clothed with overlapping scales which are responsible for the characteristic wing pattern and coloration of each species. Moth scales are modified setae. They may be hair-like, piliform scales, or flattened, lamellar scales. Lamellar scales each consist of an upper and lower wall or lamella, with a constricted stem or pedicel inserted into a socket on the wing membrane. They are of two main types (Fig. 12.4,5). In the most primitive groups, for example Zeugloptera, the lamellar scales are all more or less ovate; they are solid, without a lumen or space between the lamellae, and have a series of longitudinal ridges (Fig. 12.7) on the upper lamella (Kristensen 1970). In more advanced families normal lamellar scales usually have parallel sides and dentate ends; pigments are secreted in a space between the lamellae, and the upper one has longitudinal ridges and transverse flutes, as well as numerous small windows (Fig. 12.8) (Downey and Allyn 1975). Both types of scales may be present in advanced families, an upper layer of scales containing pigments (Fig. 12.9), and a lower layer of the primitive-type scales. Long, slender, hair-like scales that are associated with pheromone-secreting glands are sometimes hollow, with a lattice-like wall (Fig. 12.6). The wing patterns are made up of a mosaic of pigmented or reflective scales. Their colours are most frequently due to the pigments contained in the scales. The various pigmentary colours are usually produced by varying the concentration of a relatively few pigments, including melanin and pterins, but probably also carotenoids, flavones and ommachromes (Nijhout 1981). Reflective scales produce metallic or iridescent colours, which vary in shade according to the viewing angle. These do not depend on pigments but on the structure of the scales and the interference or diffraction of reflected light (Ghiradella 1984).

The males of many moths have various folds and grooves in the wings with which are usually associated specialized scales and pheromone-producing glands. Many Tortricidae, for example, have a costal fold, in which an expanded basal section of the costa of the fore wing is folded over an expandable pencil or tuft of piliform scales, which is exposed during courtship. Certain Pyralidae have a similar expanded area of the costa in the fore wing which folds beneath the wing, also covering a glandular area set with specialized piliform scales. Other special structures of the fore wings of male moths are involved in the production of sounds (see pp. 50-1). In both sexes the fore wings may bear tufts of scales which project above the usual scale covering. When the insect is at rest these tufts usually enhance its cryptic pattern and posture (see p. 52).

Wing venation The wing veins, represented by a special notation (Fig. 14), are of great value in moth classification. The more primitive groups, Micropterigidae, Agathiphagidae, Lophocoronidae and Exoporia, in which the venation of fore and hind wings is similar, are said to be homoneurous (Fig. 14.1). The more advanced groups, in which the number of veins in the hind wing is less than that of the fore wing, are said to be heteroneurous (Fig. 14.2).

There are six main series of veins in the moth wing: costa (C), subcosta (Sc), radius (R), media (M), cubitus (Cu) and anal veins (A). The costal vein runs along and strengthens the costal margin of the wing. The subcostal vein in the more primitive groups may have two branches (Sc1 and Sc2). In most groups Sc is a simple vein running from the base of the wing, more or less parallel to the costa for most of its length and finally reaching the costa. A short humeral vein running from near the base of Sc to the costa may be present. The radius has two main branches, R1 and the radial sector (Rs). R1 is nearly always a simple vein, but in Micropterigidae it may have two branches (R1a and Rlb). Rs may have as many as four branches (R2 to R5, but sometimes called Rs¹ to Rs4), and any of the veins R1 to R5 may be partially or completely fused. In the hind wing of heteroneurous forms R1 is usually fused, partly or completely, with Sc (Sc+R1), and Rs runs as an unbranched vein to the margin of the wing. The media in both fore and hind wing has an anterior branch MA and a posterior branch MP; each of these may have two branches, M1 and M2 and M3 and M4 respectively. M4 is rarely present in Lepidoptera, and the other branches of M may fuse or coalesce. Near the base of the wing the cubitus divides into two branches, an anterior branch (CuA), usually with two branches (CuA1 and CuA2), and a posterior branch (CuP). The area between the stem of CuA and the stem of R is called the discal cell or simply the cell, the distal end of which is usually ‘closed’ by cross-veins (disco-cellular veins) between M1 M2 and M3. Within the discal cell, the fused stem of R4 and R5 (R4+5) sometimes persists as the chorda, and the basal half or stem of the media is reduced or lost, except in the most primitive families. CuP persists as a strong tubular vein in the more primitive groups, but in the more advanced groups is usually reduced, vestigial or lost entirely. Frequently the basal part of this vein atrophies, while a marginal section retains its tubular form, although it is probably not functional. There is a maximum of three anal veins, but this number is frequently reduced, especially in the fore wing, in which 1A and 2A often fuse not far from the base of the wing, forming a basal fork or Y-vein, the combined stem of which runs to the margin as 1A+2A. In very narrow-winged species (e.g. Nepticulidae, Opostegidae, Gracillariidae, Lyonetiidae, Stathmopodinae, Batrachedridae, Elachistidae and Cosmopterigidae) the narrowing of the wings has been accompanied by a marked reduction in venation. As a compensation for the loss of wing area in such species, the marginal scales, especially of the hind wing, have greatly increased in length.

In addition to providing the wings with the necessary strength for flight, the veins supply the wings with blood (haemolymph), which circulates outwards from the thorax through the costal, radial and median veins, returning through the cubital and anal veins. However, the passage of the blood is obstructed to a great extent by large tracheae which occupy the main veins and their larger branches.

Flight In flight the fore and hind wings of most moths function as one by means of various wing-coupling mechanisms. In the homoneurous groups a small lobe, called the jugum (Fig. 14.1), projects from the fore wing near the anal angle. When the wings are folded at rest, the jugum in these forms is folded beneath the fore wing, but when the wings are spread in flight the jugum is extended and lies above the base of the hind wing. However, the efficiency of the jugum in wing-coupling, at least in the Hepialidae, seems doubtful since photographs of adults in flight show the wings functioning semi-independently (Mallet 1984). In some homoneurous moths there are also a few frenular bristles on the costa of the hind wing near its base. In heteroneurous moths the jugal area may be greatly reduced, when it still folds beneath the wing at rest, and in more advanced groups it may be absent. In many of these the wings are coupled together by means of a frenulum and retinaculum (Fig. 14.2). The frenulum in males is a stout, multicellular bristle which is formed by the fusion of several bristles or acanthae. It arises from a sclerotized base at the humeral angle of the hind wing and fits behind a membranous hook, the retinaculum, beneath the fore wing. More primitive forms have a broadly based and relatively short retinaculum, arising between the costa and vein Sc or on a spur of Sc, whereas in more advanced forms it is long and narrow and arises on Sc. In the females of a few families (e.g. Sesiidae, Epipyropidae, some Pyralidae) the frenulum is a single composite bristle as in males, but in most it consists of two or more slender bristles arising from a sclerotized frenulum base as in males. The retinaculum in females, however, is usually a tuft of specialized scales situated beneath the fore wing near the base of vein CuA, behind which the frenular bristles hook. In some families the tuft of retinacular scales arises on Sc, while in a few (e.g. Gelechiidae) the retinaculum is a series of curved shining scales arranged along vein R. In some Nepticuloidea the retinaculum of the male (Fig. 61.1) consists of a series of hooks along the down-curved costal margin of the fore wing, into which are hooked a series of bristles arranged along the costal margin of the hind wing, without the normal thickened frenulum base. Sometimes (e.g. Lasiocampidae, Saturniidae) both retinaculum and frenulum, as well as the frenulum base, have been lost. In some other advanced families either the retinaculum or the frenulum may be absent in females or in both sexes. When these structures are reduced or absent, the humeral area of the hind wing is usually greatly expanded and ensures that the two wings function as one. This is known as amplexiform wing-coupling. In a few families, such as Scythrididae, Lecithoceridae and Sesiidae, supplementary wing-coupling mechanisms have arisen.

Although most moths have fully developed wings and are capable of flight, in a few the wings are considerably shortened and nonfunctional or are reduced almost completely or entirely. Shortening of the wings, or brachyptery, is more commonly found in females (e.g. certain Psychidae (Pl. 23.7), Cossidae (Fig. 27.5), Geometridae and Oecophoridae), but in a few species of several families, especially those found on wind-swept Antarctic islands, both sexes are brachypterous. In the females of some species of Psychidae, Anthelidae, Lymantriidae and Arctiidae, both wings are reduced to tiny flaps, and in the more specialized Psychidae, the female is apterous and may not even shed the pupal cuticle, fertilization and oviposition occurring within the larval case. Such species tend to be sedentary and form relatively small colonies, so that dispersal usually depends on the activity of the larvae.

Abdomen

The abdomen is made up of ten segments, but segments 7 to 10 may be greatly modified to form the external genitalia. Each segment consists of a dorsal tergum with a sclerotized plate, the tergite, and a ventral sternum with a sclerotized plate, the sternite, joined at the sides by pleural membranes. However, the sternum of segment 1 is absent, except in the homoneurous families, although there it is small, especially in the Hepialidae (Kristensen and Nielsen 1980). Intersegmental membranes join all the segments together. Functional spiracles are located in the pleural membranes of the first seven segments and, in the females of a few groups such as the Hepialidae, functional spiracles are sometimes present on segment 8.

Ventral articulation of the abdomen and thorax in Ditrysia depends on muscles inserted on a pair of apodemes that usually project from abdominal sternite 2, which is ventral to tergum 1. There are two basic types (Brock 1971): the tineoid type, which occurs in the Tineoidea, Yponomeutoidea and Gelechioidea, and the tortricoid type which occurs, although somewhat variably, in the remainder of the Ditrysia. In the tineoid type, the second abdominal sternite has a pair of sublateral sclerotized thickenings, known as sternal rods or venulae, at the anterior ends of which the two slender apodemes project forwards beyond the margin of the sternite. In the tortricoid type, the apodemes are shorter and broader and are without sternal rods; the anterolateral margins of the sternite may be produced into elongate processes, the presence or absence of which provides a useful criterion in doubtful cases (Kyrki 1983b).

Paired tympanal organs are present at the base of the abdomen in the Dudgeoneidae, Pyralidae, Drepanidae and Geometridae, and in the females of Uraniidae. In the males of Uraniidae tympanal organs occur on the dorsolateral junction of abdominal segments 2 and 3. Each tympanal organ in Pyralidae is located in a single chamber with its opening directed towards the metathorax. This contains the tympanic membrane which is divided into a taut, transparent membrane proper and a translucent counter-tympanic membrane. The chordotonal sensillum is attached to the inner surface of the tympanic membrane proper and passes through the rear wall of the tympanal chamber to the meta-thoracic ganglion (Mullen and Tsao 1971; Minet 1983).

The abdomen in male moths, as well as other parts of their bodies, is the site of various glandular organs, usually associated with a wide variety of expandable tufts or brushes of hair, hair-pencils, or with special thin-walled eversible sacs known as coremata. For example, some ‘trifid’ Noctuidae have at the base of the abdomen a pair of expandable brushes of hairs which, when not in use, lie in a pair of deep pockets in segments 3 and 4. Broad scales that line each pocket have small glands at their bases, and on sternum 2 there is a special scent-producing gland, Stobbe’s gland, opening at the base of the brush. After eclosion the adult inserts its brushes into the pockets and Stobbe’s gland discharges the whole of its secretion on to the hairs, which have a lattice-like surface structure. Eversion of the brushes is produced by muscular action when the flying male approaches a receptive female. In the European species Phlogophora meticulosa (L.) the scent thus disseminated acts as an aphrodisiac and its production is normally essential for successful mating (Birch 1970).

The degree of development of such expandable brushes and their associated structures varies greatly in the Noctuidae (Birch 1972), and many species, such as Mythimna loreyimima (Rungs), are without them. Others, such as the European M. comma (L.), have air-inflated eversible coremata at the base of the abdomen that disseminate a scent. Spodoptera exigua (Hübn.) and many other species have brushes of hairs arising from a pair of eversible coremata at the base of the male valvae. Extraordinary bifid coremata occur in some Arctiidae and are everted from the posterior end of the abdomen. When fully extended, the coremata of some are as long as the whole body of the insect. They are extruded after the male has approached to within about a metre of a receptive female. Many other male moths have tufts or areas of specialized scales on the abdomen, the function of which has not been determined. Little work in this field has been done on Australian moths.

Genitalia The adult abdomen is also the site of the organs responsible for reproduction. The external genitalia of moths are derived from segments 7 to 10 and, together with the internal genitalic structures, are of major value for distinguishing species and for defining genera and higher categories.

In the male genitalia (Fig. 15.1) segment 9 forms a dorsal hood-like tegumen, which articulates with a ventral U-shaped vinculum. A blind, more or less cylindrical or trough-shaped apodeme, the saccus, sometimes projects forwards from the vinculum into the abdominal cavity. Protruding middorsally from the tegumen is the uncus, of variable shape, usually undivided, but sometimes bifid, trifid, reduced or absent. Beneath the uncus is the gnathos, formed by a pair of arms articulating basally with the tegumen and often fused medially. The anal opening of the digestive tract appears between the uncus and the gnathos, usually at the end of a protruding membranous anal tube. Sometimes hairy lateral pads or lobes, the socii (singular: socius), are present beneath the uncus. Laterally a pair of valvae (singular: valva), basally articulating with the vinculum and tegumen, represent the main clasping organs. The valva is a double-walled lobe, usually clothed with setae and externally with scales, and may bear various sclerotized spines and projections. The dorsal margin of the valva in its basal half is called the costa and is often sclerotized. Ventrally towards the base of the valva is the sacculus, which may also be sclerotized and variously ornamented with setae, spines or projections. Sometimes (e.g. some Geometridae and Noctuidae) the dorsal apical region of the valva is differentiated from the remainder as the cucullus and the ventral apical area as a more or less membranous valvula. On the inner face of the valva, about midway between its base and apex, two other sclerotized structures may be distinguished, especially in Noctuidae, a dorsal ampulla and a ventral harpe. The latter may arise from, or be connected to, the sacculus. Between the bases of the two valvae and closing the posterior end of the abdominal cavity is a transverse membrane, the diaphragma, through which the aedeagus (Fig. 15.2), a variably sclerotized tube containing the penis or vesica, passes. The inner surface of the tubular and eversible vesica often bears various sclerotized spines or other structures (cornuti) which, when the organ is everted during copulation, are exposed on the outer surface. Areas of the diaphragma surrounding the aedeagus are often sclerotized and are known as the fultura superior (above the aedeagus) and the fultura inferior (below the aedeagus). Sometimes the fultura superior is in the form of a transverse band called the transtilla, and the aedeagus is often hinged with, or even fused to, a sclerotized area of the diaphragma called the juxta. The spermatozoa are produced in paired testes and pass through paired ducts (vasa deferentia and ductus ejaculatorii) which finally unite to form a single ductus ejaculatorius leading to the vesica. The ductus ejaculatorius may enter the aedeagus at its proximal end or towards its distal end, the closed basal part then being called the coecum penis. The spermatozoa are usually enclosed during copulation in a narrow-necked sac, the sperm-atophore, formed from a secretion produced in a special section of the ductus ejaculatorius.

Fig. 15. Genitalia, Acropolitis rudisana (Tortricidae): 1,2, genitalia , ventral, aedeagus, lateral; 3, genitalia ‘i’, ventral.

The female genitalia (Fig. 15.3) are concerned with the production of eggs (ova) by the paired ovaries and the fertilization of the eggs by spermatozoa which have been received from the male during copulation and subsequently pass to the genital chamber to penetrate each egg just before it is laid. Two fundamental types of genitalia are found in female moths, monotrysian and ditrysian, but there is a third more or less intermediate type, exoporian. Those species with the monotrysian type of genitalia have a single genital aperture at or near the posterior end of the abdomen, used both for copulation and oviposition. Those with the ditrysian and exoporian types of genitalia not only have an aperture at the posterior end of the abdomen for oviposition, but also a separate copulatory aperture. Monotrysian genitalia occur throughout the Zeugloptera, Aglossata, Heterobathmiina, and in the infraorders Dacnonypha, Neopseustina, Lophocoronina and Heteroneura of the Glossata. Ditrysian genitalia are found throughout the Ditrysia, while exoporian genitalia are restricted to the infraorder Exoporia.

Nearly all female moths have four ovarioles in each of the paired ovaries. The eggs pass through paired oviducts which unite to form a common oviduct and broader genital chamber (vagina), where fertilization takes place before they reach the genital aperture (ovipore) for oviposition. The ovipore is usually located just below the anus, but occasionally the digestive tube and the vagina unite to form a cloaca and thus have a common external opening. The ovipore is nearly always flanked externally by a pair of lobes, the papillae anales, densely clothed with sensory setae, but occasionally the papillae anales may be modified and sclerotized, with a dentate margin (Fig. 11.7), or the two may be united to form a flattened sclerotized organ with serrated margin used for piercing plant tissues to deposit the eggs inside (Fig. 11.4-6).

During copulation the spermatozoa, contained in the spermatophore, are deposited in a special female sac, the bursa copulatrix; in monotrysian genitalia the bursa copulatrix opens internally from the vagina, whereas in ditrysian and exoporian genitalia it has a separate copulatory aperture on the ventral surface of the abdomen. Spermatozoa deposited in the monotrysian bursa copulatrix pass directly to the vagina and are stored in the spermatheca, from which they are liberated to fertilize the eggs. Spermatozoa deposited in the ditrysian bursa copulatrix pass through a slender duct, the ductus seminalis, to the vagina and thence to the spermatheca. They are sometimes stored temporarily in an enlargement or diverticulum of the ductus seminalis called the bulla seminalis. In exoporian genitalia the spermatozoa pass externally from the copulatory aperture along a midventral groove to enter the genital aperture and eventually the spermatheca.

The muscles which control the papillae anales and the copulatory aperture are inserted in paired, sclerotized rods or apodemes, known as apophyses. The pair running forwards from the papillae anales, called apophyses posteriores, are duplicated in certain primitive genera. The more anterior pair, the apophyses anteriores, may be divided basally into two branches or occasionally may be duplicated. The bursa