Antennal sensilla in adult Agathiphaga vitiensis dumbl. and A. queenslandensis dumbl. (Lepidoptera : Agathiphagidae)

Int. J. InsectMorphol. & Embryol., Vol. 19. No. 5/6, pp. 257-268, 19911 Printed in Great Britain

0020-7322/99 $3.00+ .()0 © 19911Pergamon Pressplc

ANTENNAL SENSILLA IN ADULT A GATHIPHAGA VITIENSIS D U M B L . A N D A. Q U E E N S L A N D E N S I S D U M B L . (LEPIDOPTERA • AGATHIPHAGIDAE)

MICHEL J. FAUCHEUX Laboratoire d'Endocrinologie des Insectes Sociaux, Universit6 de Nantes, 2 rue de la Houssini~re, 44072 Nantes C6dex 03, France

(Accepted 11 September 1990)

A b s t r a c t - - T h e antennae of both sexes of Agathiphaga vitiensis and the antenna of the female of A. queenslandensis (Lepidoptera : Agathiphagidae) were studied with a scanning electron microscope. In both sexes, 10 types of sensilla were observed on the antennae of A. vitiensis: B6hm's bristles, chaetica (types I and II), squamiformia, trichodea, biforked basiconica, short basiconica and coeloconica (types I, ll and IlI). The female of A. queenslandensis possesses the same types of sensilla, except that the biforked basiconica are flattened. Biforked sensillum basiconicum is being reported in Lepidoptera for the first time. Their presence supports Kristensen's hypothesis on the phylogeny of Lepidoptera (1984). The female of A. vitiensis possesses more sensilla than that of A. queenslar, densis. The male of A. vitiensis has a greater number of s. trichodea than the female, but the biforked sensilla basiconica are more numerous on the female antenna than on the male one. Index descriptors (in addition to those in title): Aglossata, biforked basiconica, phylogeny, sexual dimorphism, scanning electron microscopy.

INTRODUCTION

IF ONE refers to the works of B6rner (1939), Common (1975), Speidel (1977) and Kristensen and Nielsen (1983), Lepidoptera comprises 4 suborders: Zeugloptera Chapman, 1977 (the family Micropterigidae only), Aglossata Speidel, 1978 (the family Agathiphagidae only), Heterobathmiina Kristensen and Nielsen, 1979 (the family Heterobathmiidae only), Glossata Fabricus, 1775, which includes all other Lepidoptera. The Agathiphagidae ("kauri moths") contains the single genus Agathiphaga with 2 structurally similar species described from the Southwest Pacific and N.E. Australia some 30 years ago: Agathiphaga vitiensis Dumbleton, 1952 and A. queenslandensis Dumbleton, 1952. The adult moths are nocturnal and are usually readily separated by difference in wing span: A. vitiensis (23-24 mm) and A. queenslandensis (13-15 mm). The 2 species are very similar to caddisflies. Only very few adult specimens have been found in nature, (Kristensen, 1984). The limited previous knowledge of the structure and taxonomy of Agathiphaga was provided by Dumbleton (1952), Common (1970, 1973), and Robinson and Tuck (1976). Some sensory organs have been mentioned only in taxonomic reviews (Kristensen and Nielsen, 1983; Kristensen, 1984). The aim of the present study was to discover whether the antennal sensory equipment of Agathiphaga sp. possesses characters peculiar to the Agiossata suborder. 257

258

M.J. FAUCHEUX

MATERIAL AND METHODS Dried material of A. queenslandensis (one female specimen) came from the Australian National Insect Collection, and was provided by Dr E. S. Nielsen (Australia). One male and 2 females of A. vitiensiswere provided by Dr N. K. Kristensen (Denmark). For scanning electron micrographs (SEM), the specimens were coated with gold-palladium (5 A) and examined with a Jeol J.S.M. 35 C SEM. The average length and basal diameter of each sensillum were calculated from 10 measurements made on micrographs. The pore density of some sensillar types was determined from SEM micrographs at × 30,000. Counts of the sensilla were made on each segment by using the SEM at different magnifications. RESULTS

Gross antennal morphology The antennae of both species and of both sexes are filiform (Fig. 1). The male antenna of A. vitiensis (3.40 ram) is slightly smaller than the female one (3.76 ram). It has an average of 50 segments compared with 51 for the female antenna. In female A. queenslandensis, the antenna is 3.84 mm long and has 47 segments. The first 2 segments (scape and pedicel) are larger than the flagellar segments; for instance, the length and width are, 222.2 and 148.2 ~m (scape), 95.8 and 94.3 ~m (pedicel), 65.7 and 91.4 ~m (lst flagellar segment), and 48.1 and 77.4 ~m (apical segment) respectively. The scape and the pedicel are covered with irregularly distributed scales on the dorsal and ventral faces. The morphology and the length of these scales vary according to their position on the segment. Thus, at the base of the scape, scales possess 11-13 longitudinal ridges and measure 42.5-50.1 ~m (Fig. 3). Then, they gradually become narrower and longer (119.2-127.6 ~m) towards the apex of the segment, and are mixed with piliform scales possessing 5-6 ridges and measuring 63.8-106.4 ~m. On the dorsal surface of each typical flagellar segment, there are 2 rows of 13-19 scales. The upper row distally overlaps the scale bases of the next segment (Fig. 2). Scales are mixed with sensilla on the ventral face of the first 3 flagellar segments but, from the 4th flagellar segment on, scales are located only on the dorsal face. Most of the sensilla are located on the ventral face of the antenna (Fig. 2). Morphology, distribution and numbers of sensilla Both species and sexes of Agathiphagidae possess 10 types of sensilla. B6hm's bristles resemble short sensilla chaetica, which possess a cuticular collar at the base (Fig. 4). The wall surface shows slight longitudinal ridges. Their length varies from 12.8 to 31.4 ~m, but the mean length varies little between the sexes and the 2 species (Table 1). The width at the base is approximately 1.4 ~m, while the internal diameter of the alveola is 2.4 ~m (Fig. 4). The direction of the hair with regard to the antennal surface may vary (Fig. 3). No pore is visible in SEM. In both species, these sensilla are located exclusively on the scape and pedicel; there are 3 groups on the scape: an anterior and 2 lateral (Fig. 3), and 2 groups on the pedicel: an anterior and a posterior. Their numbers vary from 74 to 82 (Table 2). Sensilla chaetica type I are distinguished from other sensilla by their great length and the fact that they are vertical to the face of the antenna (Table 1, Fig. 2). They are present on both faces of the antenna. The dorsal sensilla form an angle of 30-45 ° with the antennal cuticle, unlike the ventral sensilla, which are perpendicular. They are also smaller (18,6-20.5 ~m) than the ventral ones (35.1-64.3 ~m). In A. vitiensis, the sensilla of the male are larger than those of the female, whereas the female A. queenslandensis possesses smaller sensilla than the previous species (Table 1).

A n t e n n a l sensilla in a d u l t A. vitiensis

FIG. 1. A. vitiensis m a l e . V e n t r a l surface of p r o x i m a l p o r t i o n of a n t e n n a l flagellum. B a r = 100 I.tm. F~c. 2. A. queenslandensis female. V e n t r a l surface of 39th flagellar s e g m e n t . B B = b i f o r k e d b a s i c o n i c u m ; C I = s e n s i l l u m c h a e t i c u m type I; Co = s e n s i l l u m c o e l o c o n i c u m ; Sc = scale; T = s e n s i l l u m t r i c h o d e u m ; circule = s o c k e t of scale. B a r = 20 I~m. FIG. 3. A queenslandensis female. B 6 h m ' s bristles on s c a p e (arrows): 2 lateral groups. B a r = 20 txm.

259

260

M . J . FAUCHEUX

TABLE 1. THE LENGTH ANO BASAL WIDTH (MEAN ~+ S . E . , IN i,Lm) OF SENSILLA OF A. vitiensis (MALE AND FEMALE)

AND A. queenslandensis (FEMALE) (n = 30)

A. vitiensis Sensilla

B6hm's bristles

length

14.6 _+ 2.9

15.1 _+ 2.4

A. queenslandensis basal width

1.3 _+ 0.2

1.4 _+ 0.1

length

basal width

15.8 _+ 3.7

1.4 +_ 0.3

Chaetica I

48.1 _+ 11.5 35.3 _+ 8.1

1.4 _+ 0.2

1.3 _+ 0.2

31.5 _+ 9.3

1.5 _+ 0.2

Chaetica I1

25.7 _+ 6.2

28.6 + 7.9

1.3 _+ fl.1

1.2 _+ 0.l

26.3 _+ 7.4

1.3 _+ 0.1 2.7 + 0.2

Squamiformia

73.8 _+ 5.3

74.2 _+ 3.4

2.7 _+ 0.2

2.6 _+ 0.3

79.6 _+ 6.5

Trichodea

35.9 _+ 3.6 28.1 _+ 2.8

1.3 _+ 0.1

1.3 _+ 0.2

32.6 _+ 5.7

1.3 _+ 0.!

Biforked basiconica

22.3 _+ 4.1

23.5 _+ 3.7

2.7 _+ 0.3

2.8 _+ 0.2

12.5 _+ 4.9

2.5 _+ 0.2

Short basiconica

5.1 _+ 0.6

5.1 _+ 0.4

1.4 _+ 0.3

1.5 _+ 0.1

4.9 _+ 0.9

1.4 _+ 0.I

Coeloconica I, II, III

3.6 _+ 0.9

3.4 _+ 1.1

1.5 _+ 0.1

1.5 _+ 0.2

3.4 _+ 0.5

1.5 _+ 0.1

As in other Lepidoptera, the hair is covered with longitudinal grooves and annular ridges (Fig. 6). Sensilla chaetica I are thick-waUed: 0.5 Ixm in A. queenslandensis, 0.60.8 Ixm in A. vitiensis (Fig. 7). The lumen diameter reaches 0.3-0.5 txm in both species. The terminal pore is shown in Fig. 6. The sensilla tend to form a complete circle around each flagellar segment, and are the only ones present even on the dorsal face (Fig. 21). There are 5-7 sensilla per segment, except for the apical segment, which bears 9-12 sensilla. There is a larger number of sensilla in the female than in the male of A. vitiensis. The female A. queenslandensis is well provided with sensilla than A. vitiensis (Table 2). The morphology and length of sensilla chaetica type II are intermediate between B6hm's bristles and sensilla chaetica type I (Table 1). The cuticular socket of these tapering sensilla is distinct, but less pronounced than in sensilla type I (Fig. 5). The tip as well as the wall lack pores. These sensilla are lolcated only on the scape, the pedicel and the 1-5 flagellar segments. Their numbers vary from 10 to 16 in the 2 species (Table 2). Sensiila squamiformia resemble narrow scales, but they are embedded in a socket (Fig. 9). Their length varies little from one sex or species to another (Table 1). They have no pores. These sensilla are scattered among the scales on the dorsal and ventral faces of the scape and the pedicel. Their numbers are relatively small: 15-23 (Table 2). Transitional forms between sensilla squamiformia and sensilla chaetica type II are observed on the scape (Fig. 10). Sensilla trichodea can be easily distinguished from sensilla chaetica type I, because they are often curved just above their base (Figs 2, 15). They are deprived of a basal socket and their walls possess oblique ridges (Fig. 11), which fuse on one side. Pores are located between the ridges, but they are often invisible on our SEM micrographs. Sensilla trichodea are thin-walled in the 2 species; the diameter of the lumen is 0.7-0.9 p~m and the wall measures only 0.2 txm (Fig. 8). They are longer in the male of A. vitiensis than in the female. Moreover, the sensilla are longer in female A. queenslandensis than those of female A. vitiensis (Table 1). They are the most numerous antennal sensilla: 39.0-66.8% in the 2 species (Table 2). Sensilla trichodea are 1.7 times more numerous in the male than in the female A. vitiensis. The latter possesses 1.6 times more sensilla than the female A. queenslandensis. In the 2 species, sensilla are scattered over the entire unscaled surface of each segment (Fig. 21).

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FIG. 4. B a s a l p a r t of one B 6 h m ' s bristle of f e m a l e A. queenslandensis (star). Bar = 2 i~m. Fro. 5. S e n s i l l u m c h a e t i c u m type II on the p e d i c e l B a r = 2 i-tin. Fro. 6. A p e x of a sensiUum c h a e t i c u m type I s h o w i n g apical p o r e (arrow). Bar = 0.5 i,tm. Fie. 7. B a s a l p a r t of a b r o k e n s e n s i l l u m c h a e t i c u m type I located on dorsal surface of a n t e n n a , Bar = 1 t~m.

A n t e n n a l sensilla in adult A. vitiensis

Biforked sensilla basiconica:

263

this sensilla type is characteristic of the genus

Agathiphaga. Some sensilla are entirely biforked from base to tip (Fig. 12), while others ramify into 2 branches at a certain distance from the base (Figs 13, 15), the two situations occurring on the same flagellar segment. They appear as "ear-like sensilla" in A. queenslandens,is (Fig. 12). Biforked sensilla basiconica measure from 12.5 to 23.5 txm (Table 1). They are longer in A. vitiensis than in A. queenslandensis. Pronounced longitudinal st~dations characterize the wall surface (Fig. 12). In fact, these 16-19 grooves correspond to lines of pores, which exist on the 2 faces from the base of the sensilla upwards (Fig. 13). The pore density in the 2 sexes of A. vitiensis is 9-11/~m 2 (Fig. 14). Biforked s. basiconica are always more numerous in the females than in the males of A. vitiensis (Table 2). Furthermore, the female of A. vitiensis is more richly provided with these sensilla than that of A. queenslandensis. On a typical antennal segment, these sensilla are more common in the neighbourhood of the scales (Fig. 21). Short sensilla basiconica possess a basal cupola (Fig. 16) and are 4.9-5.1 ~xm long (Table 1). It was impossible to discover any pore. At most, there is only one sensillum per segment ('Fable 2), located near sensilla coeloconica (Fig. 21). Three types of sensilla coeloconica can be distinguished in both sexes of the 2 species: Co I, Co II and Co III. Each of these types is sunk in a pit. Sensilla coeloconica type I are the most common type on the lepidopteran antennae. The peg (3.4-3.6-1xm long) is surrounded by a circular fence of microtrichia (Fig. 17); it possesses longitudinal grooves with pores located between 2 adjacent grooves. The distribution of these sensilla is very unusual. For example, in both the male and the female of A. vitiensis, there are 44--45 sensilla on the 1st flagellar segment, 14-16 on the 2nd, 11-13 on the 3rd, and 5--6 on the 4th; thereafter, the following segments have only 1-2 sensilla per segment, except for the apical segment, which bears 5 sensilla. In the female A. queenslandensis, the same type of distribution can be observed, but the 1st segment has only 28 sensilla. Sensilla coeloconica type II are composed of a peg (4.4-4.7-1xm long) without a cuticular fence (Fig. 18). The peg has 2-3 slightly longitudinal ridges and is perforated by an apical pore (Fig. 19). There are only 2 sensilla per segment. Sensilla coeloconica type III have a conical and smooth peg 2.2-2.4-~m long (Fig. 20). In SEM, they seem deprived of pores. There are between 0 and 4 sensilla per segment. On a typical flagellar segment, the 3 types of sensilla coeioconica are located in the distal part (A. queenslandensis) or in the median part (A. vitiensis) of the segment, in the region between the scaled and the unscaled faces (Fig. 21). The total numbers of sensilla coeloconica do not show dimorphism, but they are larger in A. vitiensis than in A. queenslandemis (Table 2). In short, the 2 species of Agathiphaga possess identical types of sensilla. They can, however, be distinguished by the form of the biforked sensilla basiconica. The total number of sensilla on the antenna of A. vitiensis is larger than in A. queenslandensis.

FIG 8. Oblique break through the hair of a sensillum trichodeum. Bar = 1 Ixm. FIG 9. Sensillum squamiformium on scape of female A. vitiensis. Bar = 10 txm. FIG. 10. Transitional form between sensillum squamiformium and sensillum chaeticum type II on scape. Bar = 10 ixm. FIG. 11. Middle part of a sensillum trichodeum with oblique cuticular ridges. Bar = 1 i.tm.

264

M . J . FAUCHEUX

FIG. 12. B i f o r k e d s e n s i l l u m b a s i c o n i c u m of A. queenslandensis, s h o w i n g grooves. B a r - 4 ~m. FIG. 13. B a s a l p a r t of b i f o r k e d s e n s i l l u m b a s i c o n i c u m on 33rd flagellar s e g m e n t of m a l e A. vitiensis, s h o w i n g g r o o v e s a n d pores. B a r = 2 I~m. FIG. 14. O b l i q u e b r e a k t h r o u g h peg of a b i f o r k e d s e n s i l l u m b a s i c o n i c u m s h o w i n g pores. B a r = 1 ixm. FIc,. 15. D e t a i l of 21st flagellar s e g m e n t of a m a l e A vitiensis. T - sensillum t r i c h o d e u m ; star = b i f o r k e d s e n s i l l u m b a s i c o n i c u m . B a r = 10 ~tm.

A n t e n n a l sensilla in adult A. vitiensis

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DISCUSSION

In other Lepidoptera, the B6hm's bristles are deprived of a pronounced collar and the hairs are smooth (Cornford et al., 1973; Sellier, 1977; Faucheux 1985, 1989). This is, therefore, the first time that ridged B6hm's bristles have been described in moths. These sensilla are considered as proprioceptors (Schneider, 1964). No significant difference was observed between the numbers of the sensilla chaetica type I either in the 2 species of Agathiphagidae or between the sexes. They may indicate that the contact chemoreceptive function of the antenna takes places in the same way in the two sexes. Sensilla chaetica type II have been described so far only in the small ermine moths (Van der Pers et al., 1978; Cuperus, 1983) and in the Nepticulidae (Nieukerken and Dop, FIG. 16. Short sensillum basiconicum on 2nd flagellar segment. Bar = 1 Ixm, FIG. 17. Sensillum c o e l o c o n i c u m type I on 3rd flagellar segment. Bar = 3 ~m. FIG. 18. Sensillum c o e l o c o n i c u m type II on 5th flagellar segment. Bar = 1 i~m. FIG, 19. Detail of apical pore of sensillum c o e l o c o n i c u m type II. Bar = 0.5 ixm. FI(~, 20. Sensillum c o e l o c o n i c u m type Ill on 3rd flagellar segment. Bar = 1 ~tm.

266

M . J . FavcHEux

1987). Like the latter authors, we suggest that sensilla chaetica type II of the 2 species of Agathiphagidae might be mechanoreceptors. Sensilla squamiformia were mentioned for the first time by Schneider (1964) in Bombyx mori, and are considered as mechanoreceptors. Externally, the male and female sensilla trichodea of A. vitiensis and A. queenslandensis are identical. According to George and Nagy (1984), the pattern of the cuticular ridges, as used by Jefferson et al. (1970) or Albert and Seabrook (1973), is not a satisfactory means of classification. Indeed, in the tineid moths, Tineola bisselliella and Monopis crocicapitella, the ultrastructure of the sensilla trichodea revealed at least 2 distinct types (Faucheux, 1987). Not having undertaken ultrastructural studies in the Agathiphagidae, we have been able to describe only a single morphological type of sensilla trichodea. These sensilla have been involved in pheromone perception (Kaissling, 1971; Steinbrecht, 1973; George and Nagy, 1984; Keil, 1984; Zacharuk, 1985). This is the first time that numerous biforked sensilla basiconica have been described in the Lepidoptera. Biforked sensilla have been identified in the coleopteran, Monochamus sp. (Dyer and Seabrook, 1975), in scorpionflies (Slifer, 1975) and in thrips (Slifer and Sekhon, 1974). In the lepidopteran, Opisina arenosella, certain sensilla basiconica are occasionally forked at the distal end (Jayaprakash and Prabhu, 1986). We have also observed, on a few specimens of T. bisselliella, the presence of biforked sensilla basiconica, but this seems to be rare (Faucheux, 1979). The form of biforked sensilla varies according to the species of Agathiphaga, to sex and on the same segment of an individual. The position of these sensilla on any flagellar segment is peculiar to the Agathiphagidae: in both species, they cover the whole of the ventral face. The relatively large number of biforked sensilla hasiconica of the 2 Agathiphagidae confirms the results described in the Tineidae (Faucheux, 1987). Similarly, as in T. bisselliella and Trichophaga tapetzella (Faucheux, 1989), the males of A, vitiensis have far fewer sensilla basiconica than the females. Judging from their ultrastructural properties, sensilla basiconica function as chemoreceptors; they may respond to odours of food and oviposition sites. This could be the reason for their greater number in female Agathiphaga sp. The sensilla coeloconica type I resemble the same sensilla in the other Lepidoptera. Their distribution is very different from that reported in various Lepidoptera (Albert and Seabrook, 1973; Wall, 1978; Faucheux, 1985). The presence of a large number of sensilla coeloconica type I on the 1st flagellar segment of Agathiphaga sp. is therefore a specific characteristic. If the flagellum has been for the most part destroyed by an accident, the function attributed to these sensilla partly persists in both species. The sensilla coeloconica may act as receptors for plant odours, as has been found in other insects (reviews in Altner and Prillinger, 1980; Zacharuk, 1985). Sensilla coeloconica without a circular fence have been described in a few moths; they are always present in small numbers (Cornford et al., 1973; Nieukerken and Dop, 1987). In typical sensilla coeloconica of lepidopteran species, with or without a fence, one row of pores is visible between adjacent grooves (Cuperus, 1985). Sensilla coeloconica type II of Agathiphaga sp. differ from the typical sensilla coeloconica by the lack of pronounced longitudinal grooves and of wall pores, and by the presence of an apical pore. This sensillar type has not been described on the antenna of other Lepidoptera. The external structure of sensilla coeloconica type III Agathiphaga sp. is very similar

Antennal sensilla in adult A. vitiensis

267

to the c o e l o c o n i c s e n s i l l u m of the c a m e l cricket, T a c h y c i n e s a s y n a m o r u s , which has b e e n i d e n t i f i e d as t h e r m o - a n d h y g r o r e c e p t i v e by N i s h i k a w a et al. (1985). E x t e r n a l f e a t u r e s suggest t h a t sensilla c o e l o c o n i c a t y p e I I I m a y be n o n - p e r f o r a t e d .

CONCLUSION The antennal sensory e q u i p m e n t of A. vitiensis and A. queenslandensis possesses some p e c u l i a r c h a r a c t e r i s t i c s : the p r e s e n c e o f b i f o r k e d sensilla b a s i c o n i c a a n d o f 3 t y p e s o f sensilla c o e l o c o n i c a . A s r e g a r d s t h e p h y l o g e n y o f the L e p i d o p t c r a ( N i e l s e n , 1982): " M o s t a u t h o r s h a v e f a v o u r e d the h y p o t h e s i s t h a t the p r i m a r y d i c h o t o m y in the L e p i d o p t e r a lies b e t w e e n Z e u g i o p t e r a a n d all r e m a i n i n g L e p i d o p t e r a . H o w e v e r , o n g o i n g a n a t o m i c a l studies on A g a t h i p h a g i d a c p r o v i d e e v i d e n c e that the p r i m a r y d i c h o t o m y might a l t e r n a t i v e l y lie b e t w e e n A g l o s s a t a a n d Z e u g l o p t e r a + G l o s s a t a , a n d the possibility t h a t it lies b e t w e e n Z e u g l o p t e r a + A g l o s s a t a a n d G l o s s a t a c a n n o t be e n t i r e l y r u l e d o u t ( K r i s t e n s e n and N i e l s e n , 1979." W e b e l i e v e t h a t t h e p r e s e n c e o f b i f o r k e d sensilla b a s i c o n i c a offers a f u r t h e r a r g u m e n t for o n e o f the a b o v e - m e n t i o n e d h y p o t h e s e s . Z e u g l o p t e r a possess a n t e n n a l ascoids, but no sensilla auricillica ( K r i s t e n s e n a n d N i e l s e n , 1979) o r b i f o r k e d sensilla b a s i c o n i c a ( p e r s o n a l o b s e r v a t i o n s ) . A g l o s s a t a i~ e n d o w e d with b i f o r k e d sensilla b a s i c o n i c a (this p a p e r ) . F i n a l l y , H e t e r o b a t h m i i n a ( K r i s t e n s e n a n d N i e l s e n , 1983; K r i s t e n s e n , 1984) a n d G l o s s a t a have sensilla auricillica, which are c o n s i d e r e d as b e i n g f l a t t e n e d sensi][la b a s i c o n i c a ( W a l l , 1978). T h e s e results, t h e r e f o r e , a g r e e with K r i s t e n s e n ' s (1984) h y p o t h e s i s : ( Z e u g l o p t e r a + [ A g l o s s a t a + ( H e t e r o b a t h m i i n a + G l o s s a t a ) ] ) . T h e p r e s e n c e o f b i f o r k e d sensilla b a s i c o n i c a exclusively in A g l o s s a t a m a y also be c o n s i d e r e d as an a r g u m e n t in f a v o u r o f the existence of this s u b o r d e r . Acknowledgements -- I express my sincere gratitude to Dr E. S. Nielsen, CSIRO, Canberra, Australia and Dr

N. P. Kristensen, Copenhagen, Denmark, for providing material; to Mr A. Barreau, Centre of SEM, Nantes, for taking the micrographs, Mrs O. AumaiUe, for developing them, and Mr V. Ballardini for help with the translation.

REFERENCES ALBERT,P. J. and W. D. SEABROOK.1973. Morphology and histology of the antenna of the male eastern spruce budworm, Choristoneura fumiferana (Clem.) (Lepidoptera : Tortricidae). Can. J. Zool. 51: 443-48. ALTNER, H. and L. PrULHNGEm 1980. Ultrastructure of invertebrate chemo-, thermo-, and hygroreceptors and its functional significance. Int. Rev. Cytol. 67: 69-139. B6RNER, C. 1939. Die Grundlagen meines Lepidopterensystems. Verh. VII. Int. Kongr. Entomol. (Berlin). 2: 1372-1424. COMMON, I. F. B. 1970. Lepidoptera, pp. 765-866. In MACKERRAS,1. M. (ed.), The Insects o f Australia. Melbourne University Press, Melbourne. COMMON, I. F. B. 1970. Lepidoptera, pp. 765-866. In MACKERRAS, I. M. (ed.) The Insects o f Australia. Melbourne University Press, Melbourne. COMMON,I. F. B. 1975. Evolution and classification of the Lepidoptera. Annu. Rev. Entomol. 20: 193-203. CORNFORD,M. E., A~. R. WAYNEand J. A. KLUN. 1973. Scanning electron microscopy of antennal sensilla of the European corn borer, Ostrinia nubilalis. Ann. Entomol. Soc. Amer. 66: 1079-88. CUPERUS,P. L. 1983. Distribution of antennal sense organs in male and female ermine moths, Yponomeuta vigintipunctatus (Retzius) (Lepidoptera : Yponomeutidae). Int. J. Insect Morphol. Embryol. 14: 17991. CUPERUS, P. L. 1985. Inventory of pores in antennal sensilla of Yponomeuta spp. (Lepidoptera : Yponomeutidae) and Adoxophyes orana F.v.R. (Lepidoptera : Tortricidae). Int. J. Insect Morphol. Embryol. 14: 347-59. DUMaLETON,L. F. [952. A new genus of seed-infesting Micropterygid moths. Pacif. Sci. 6: 17-29.

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M . J . FAUCHEUX

DYER, L. J. and W. D. SEABROOK. 1975. Sensilla on the antennal flagellum of the sawyer beetles Monochamus notatus (Drury) and Monochamus scutellatus (Say) (Coleoptera : Cerambycidae). J. Morphol. 146: 513-32. FAUCHEUX, U . J. 1979. Les r6cepteurs sensoriels de l'antenne de Tineola bisselliella Humm. (L6pidopt6re Tin6id6). Bull. Soc. Sci. Nat. Ouest Fr. (N.S.) 1: 7-14. FAUCHEUX, M. J. 1985. Morphology and distribution of antennal sensilla in the female and male clothes-moth, Tineola bisselliella Humm. (Lepidoptera : Tineidae). Can. J. Zool. 63: 355~52. FAUCHEUX, M. J. 1987. Recherches sur les organes sensoriels impliqu6s dans le comportement de ponte de deux L6pidopt~res h larves k6ratinophages: Tineola bisselliella Humm. et Monopis crocicapitella Clem. (Tineidae). Th6se doct. 6tat, Univ. Nantes. FAUCHEUX, M. J. 1989. Antennal sensilla in male and female carpet moth, Trichophaga tapetzella L. (Lepidoptera : Tineidae): a scanning electron microscopic study. Ann. Soc. Entomol. Ft. (N.S.). 25: 83-93. GEORGE, J. A. and B. A. L. NAGY. 1984. Morphology, distribution, and ultrastructural differences of sensilla trichodea and basiconica on the antennae of the oriental fruit moth, Grapholitha molesta (Busck) (Lepidoptera : Tortricidae). Int. J. Insect. Morphol. Embryol. 13: 157-70. JAYAPRAKASH, R. and V. K. K. PRABHU. 1986. Forked sensillum on the antenna of Opisina arenosella Walker (Lepidoptera : Cryptophasidae) Entomon 11: 127-28. JEFFERSON, R. N., R. E. RUBIN, S. U. McFARLAND and H. H. SHOREY. 1970. Sex pheromones of noctuid moths. XXII. The external morphology of the antenna of Trichoplusia ni, Heliothis zea, Prodenia ornithogalli and Spodoptera exigua. Ann. Entomol. Soc. Amer. 63: 1227-38. KAISSLING, K. E. 1971. Insect olfaction, pp. 351-431. In L. M. BEIDLER(ed.) Handbook of Sensory Physiology, Vol. IV, Chemical Senses 1, Olfaction. Springer, Berlin. KEIL, T. A. 1984. Reconstruction and morphometry of silkmoth olfactory hairs: a comparative study of sensilla trichodea of the antennae of male Antheraea polyphemus and Antheraea pernyi (Insecta, Lepidoptera). Zoomorphology 104: 147-56. KRISTENSEN, N. P. 1984. Studies on the morphology and systematics of primitive Lepidoptera (Insecta). Steenstrupia 10: 141-91. KRISTENSEN, N. P. and E. S. NIELSEN. 1979. A new subfamily of micropterigid moths from South America. A contribution to the morphology and phylogeny of the Micropterigidae, with a generic catalogue of the family (Lepidoptera : Zeugloptera). Steenstrupia 5: 69-147. KRISTENSEN, N. P. and E. S. NIELSEN. 1983. The Heterobathmia life history elucidated: Immature stages contradict assignment to suborder Zeugloptera (Insecta, Lepidoptera). Z. Zool. Syst. Evolut.-forsch. 21: 101-24. NIELSEN, E. S. 1982. Review of the higher classification of the Lepidoptera, with special reference to lower heteroneurans. Ty6 to Ga. 33: 98-101. NIEUKERKEN, E. J. VAN and H. DoP. 1987. Antennal sensory structures in Nepticulidae (Lepidoptera) and their phylogenetic implications Z. Zool. Syst. Evolut.-forsch. 25: 104-26. NISHIKAWA, M., F. YOKOHARI and T. ISHIBASHI. 1985. The antennal thermoreceptor of the camel cricket, Tachycines asynamorus. J. Insect Physiol. 31: 517-24. ROBINSON, G. S. and K. R. TUCK. 1976. The Kauri Moth Agathiphaga. A Preliminary Report. British Museum (Natural History), London. SCHNEIDER, D. 1964. Insect antennae. Annu. Rev. Entomol. 9: 103-22. SELLIER, R. 1987. Etude ultramorphologique des sensilles antennaires des S6siid6s. Essai sur l'origine et les 6tapes de la morphogen6se des sensilles antennaires des L6pidopt~res. Ann. Soc. Entomol. Fr. (N.S.). 13: 346~57. SLIVER, E. H. 1975, Sense organs on the antennal flagellum of two species of scorpionflies (Mecoptera). Int. J. Insect Morphol. Embryol. 4: 467-75. SLIFER, E. H. and S. S. SEKHON. 1974. Sense organs on the antennae of two species of thrips (Thysanoptera : Insecta). J. Morphol. 143: 445-56. SPEIDEL, W. 1977. Ein Versuch zur Unterteilung der Lepidopteren in Unterordnungen. Atalanta, Wi~rzburg. 8: 11~21. STEINBRECHT, R. A. 1973. Die Feinbau olfaktorischer Sensillen des Seidenspinners (Insecta, Lepidoptera). Z. Zellforsch. 139: 533~55. VAN DER PERS, J. N. C. and C. K. DEN OTrER. 1978. Single cell responses from olfactory receptors of small ermine moths (Lepidoptera : Yponomeutidae) to sex attractants. J. Insect Physiol. 24: 33743. WALL, C. 1978. Morphology and histology of the antennae of Cydia nigricana (F.) (Lepidoptera : Tortricidae). Int. J. Insect. Morphol. Embryol. 3: 237-50. ZACHARUK, R. Y. 1985. Antennae and sensilla: pp. 1 70. In G. A. KERKUT and L. 1. GILBERT (eds): Comprehensive Insect Physiology, Biochemistry and Pharmacology, Vol. 6. Pergamon Press, Oxford.