Journal of the American Mosquito Control Association, 18(2):73-80,2OO2 Copyright @ 2OO2by the American Mosquito Control Association, Inc.

MOUTHPARTS OF MALE AEDES (STEGOMTA) MOSQUTTOES

ISRA WAHID, TOSHIHIKO SUNAHARA rNo MOTOyOSHI MOGI

Division of Parasitoktgy, Department of Microbiology, Saga Medical School Nabeshima 5-1-1, Saga 849-8501, Japan

ABSTRACT- Mouthparts of adult males of l7 strains of 8 species from the subgenus Stegomyia of the genus Aedes, inchtding 5 strains of Aedes aegypti and 6 strains of Aedes albopictus, were examined. Lengths of maxillae, mandibles, maxillary palpi, and proboscises were measured under light microscopy and their detailed structures were examined by scanning electron microscopy. Lengths were presented as ratios to proboscis lengths. In contrast to previous reports, mandibles were found in all 5 strains of male Ae, aegypti examined. Variations in maxillary and mandibular lengths were significant among strains, even within,4e. aegypti and Ae. albopictus. High variation of these structures among and within species indicates that the average length of these structures in only 1 species may not be a reliable representative of a subgenus, and those of I strain may not be reliable fbr a species. However, their range in length (maxillae O.f3 {.50, mandibles O.04-{.17 length of the proboscis) may be regarded as a subgeneric attribute. Maxillae and mandibles distinctly shorter than the proboscis, together with their delicate structures and the large coefficient of variation, suggest that they exist only as vestigial structures. A positive correlation was found between lengths of maxillae and those of mandibles, but mandibles are usually shorter than maxillae. The hypopharynx is discernible from the labium wall by its texture and border, and this suggests that it was a free stylet in the past.

KEY WORDS Aedes, Stegomyfui, maxllla, mandible. hypopharynx. male mouthparts

INTRODUCTION As a result of the elevation of the subgenus Och- lerotatus to generic rank by Reinert (2000), the Because most female mosquitoes feed on blood, subgenera Stegomyia and Aedes remain in the ge- their mouthparts are highly specialized for piercing nus Aedes, whereas subgenera Ochlerotatus and the host skin and sucking blood. The piercing- Finlaya belong to the genus Ochlerotatus. To avoid sucking tools, known collectively as the fascicle, confusion, references to previous comparative mor- contain I pair of teeth-bearing maxillary stylets, I phological studies of subgenera will be on the basis pair of mandibular stylets, a labrum, and a hypo- of the older classification. The implications of the pharynx with its salivary canal. All these structures Reinert classification on these studies will be dis- are packed in the gutterlike labium and constitute cussed later. a proboscis. Marshall and Staley (1935) reported variations of The labrum forms a food canal and provides ri- maxillae and mandibles among male mosquitoes gidity for the fascicle, whereas the maxillae anchor from the United Kingdom. They found maxillary themselves to the host skin by their teeth. Whether stylets to be present in 8 subgenera examined, but the mandibles play an active role during piercing the lengths of the stylets were found to be highly as in other bloodsucking nematoceran flies variable arnong the subgenera, whereas mandibles (Downes 1970), or simply serve as a closure of the were absent in subgenera Aedes and Ochlerotatus distal opening of the labral food canal (Clements of the genus Aedes. Marshall and Staley regarded 1992) is not clear. The hypopharynx, which par- the lengths of these structures as characteristic to tially makes the ventral closure of the labral food each subgenus. However, because they examined canal, enters the host skin together with other parts only l-4 species from the United Kingdom for and releases saliva from a gutter on its surface (the each subgenus, whether these attributes are com- salivary canal) during feeding. mon throughout each subgenus is not clear. Vizzi Male mosquitoes do not take blood. Their food (1953) reported a wide range of individual variation sources are mainly floral and extrafloral nectaries, in mouthpart lengths of male Anopheles quadri- honeydew (Foster 1995), or even plant tissue maculatus Say, even for specimens taken from I (Schlein and Muller 1995). Their mouthparts are laboratory colony. not developed for piercing. The maxillae and man- The subgenus Stegomyia of the genus Aedes in- dibles are much shorter than the proboscis (Vizzi cludes vectors of human filariasis and a number of 1953, Snodgrass 1959, Downes 1970, Clements viral diseases and is a dominant subgenus in the 1992) and are considered to be functionless (Vizzi Oriental Region (Huang 1979). However, reports 1953, Snodgrass 1959), as in nonbloodsucking ne- on mouthparts of male Stegomyia are limited to matocerans (Downes l97O). On the other hand, the those dealing with Aedes aegypti (L.). Christophers labrum and the hypopharynx do reach the tip of the (1960) and Lee (1974) described the strucrures of proboscis. The hypopharynx, with its salivary ca- mouthparts of both males and females under light nal, fuses with the inner wall of the labium and may microscopy and scanning electron microscopy, re- form the ventral closure of the labral food canal spectively. Both of these authors stated that man- (Clements 1992). dibles are absent in males of Ae. aegypti.

73 JounNel op rnr AunnrcAN Moseurro CoNrnol AssocrartoN Vor. 18,No.2

Table l. Aedes (Stegomyta) species and strains examined.

Species Strain

Aedes aegypti Makassat Indonesia 20 Liverpoolr 18 Jakarta, Indonesia 13 Timor, Indonesia 15 Polewali, Indonesia 20 Aedes albopictus Matsumoto, Japan 18 Polewali, Indonesia 12 Tanegashima, Japan 15 Makassar, Indonesia I I Okinawa, Japan 11 Mambi, Indonesia l0 Aedes paullusi Seram, Indonesia 20 Aedes scutellaris Seram, Indonesia 20 Aedes riversi Kabeshima, Japan l7 Aedes flavopictus Seburi, Japan 10 Maxilla Aedes galloisi Kyongi-do, Korea 18 Aede s pseudoalbolineatus Mambi, Indonesia 9

' The Liverpool strain originally was collected in Thailand. E l Our preliminary observation suggested the pres- (s ence of maxillae and mandibles of males in some o species of the subgents Stegomyia. Thus, our ob- $ 3 jectives were to describe the mouthparts of male o c Aedes (Stegonyla) species, with confirmation of the c morphological status of mandibles of Ae. aegypti males; and to examine whether the lengths of max- illae and mandibles are common attributes throush- out species belonging to this subgenus. Maxillary

MATERIALS AND METHODS

Specimens included 17 strains of 8 species from Fig. 1. Head and mouthparts of a male of Aedes 3 species groups of Stegomyia: Ae. aegypti repre- (Stegomyia). sented the aegypti group; the scutellaris group in- cluded Aedes alboplcrzs (Skuse), Aedes paullusi Stone and Farner, Aedes scutellaris (Walker), Aedes us to compare the relative lengths of the structures, riversi Bohart and Ingram, Aetles flavopictus Ya- because the absolute values are affected by body mada, and Aedes galloisi Yamada; and Aedes pseu- size. We measured the lengths of maxillary palpi, doalbolineatus Brug represented the albolineatus because they are a well-developed functional organ group. For Ae. aegypti and Ae. albopictus,5 and 6 in males (Clements 1992) and are connected di- strains were examined, respectively (Table 1). lden- rectly to the base of maxillary stylets. The lengths tifications were based on keys of Wepster (1954), of maxillary palpi can be used to compare the ex- Huang (1979), and Tanaka et al. (1979). Numbers tent of variation between structures with functions of specimens varied from 9 to 20 individuals, de- and those without function. pending on availability. Specimens were reared Specimens in 7O7o ethanol were transferred to from larvae collected in the field or obtained from 2%oKOH solution and heated at 50'C for 2 h. They laboratory colonies, and kept alive for at least 24 h were then dehydrated by passage through 7O7o, after emergence. Until examination, specimens 9OVo. and 99Vo ethanol in this order, and stained were kept in 7O7o ethanol. with acid fuchsin. Specimens were kept in the stain- Because the labium, labrum, and hypopharynx in ing solution at least for 2 h. Just before examina- male Stegomyia arc almost the same length and tion, the specimens were put on tissue paper for a reach the tip of the proboscis, we measured only few seconds to absorb the stain, and then put on a the lengths of maxillae, mandibles, maxillary palpi, microscope slide. One or 2 drops of Methyl Cel- and the proboscis (the length of the labium from losolve (Nakarai Chemicals, Ltd., Kyoto, Japan) the base of the prementum to the tip of the labella) were placed on the specimen, which was then ex- (Fig. 1). All measurements were converted to mil- amined under both dissecting and compound mi- limeters and then presented as ratios of proboscis croscopes. lengths (Marshall and Staley 1935). This enabled First, the head was separated from the body by

JuNe2002 Mournpanrs or Mala AEDES (SrEGoMya) MoseurroEs

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E€?EEE'P€ge ,EA7;iEf::EBis€!!; sB$€;;;€i€€iiii$t F E": - i.: *-=9\S€ -E:€:ES$eoE\! $iii$ir€sFP " \€ :$$$E.$ii$$E*;;; { FseIFF$$$s,$=:€ ii i s r! r<=ss'\ i Fig. 5. Average lengths of maxillary palpi of male Fig. 6. Variation of maxillary lengths of male Stego- Stegomyia. Proboscis length : l. myia. The box indicates the interquartile range with the median as a transversal line; upper and lower whiskers are maximum and minimum values within 1.5 of the inter- riversi, Ae. flavopictus, and Ae. galloisi. However, quartile range. Outliers (more than 1.5 times of interquar- in Ae. pseudoalbolineatus, lengths of maxillary pal- tile ranges) are plotted separately and marked with dense pi are about one half of the proboscis length (Fig. circles. Vertical gray bars across the medians are957o con- 5). Statistical tests showed significant differences fidence intervals. Horizontal lines at the bottom of the among all the strains examined (Kruskal*Wallis graph are (A) strains of Aedes aegypti, (B) strains ofAe. test, 11 : 203.7, df : 16, P < 0.001). Significant albopictus, and (C) scutellaris group. The aegypti group differences were found even within the same spe- and,albolineatus group are represented by Ae. aegypti and Ae. pseudoalbo Iineatus, respectively. cies (Ae. aegypti, H: 11.6, df : 4, P < O.021; Ae. albopictus, H : 23.3, dt : 5, P < 0.OOl). Maxillae are much shorter than proboscises, with : 148.5, df : 16. P < 0.001). and also withinAe. a range of 0.13-0.5 of the proboscis lengths. The aegypti (H : 23.7, dt : 4, P < 0.001) anrJ Ae. Kruskal-Wallis test showed signiflcant differences albopictus (H : 13.7, df : 5, P < 0.05). among all the strains examined (H : 140.6, df : Figure 7 shows that within the scutellaris group 16, P < 0.001), within Ae. aegypri (H : 36.1, df (except Ae. albopiuus), lengths of mandibles of Ae. : 4, P < 0.001), and within Ae. albopictus (H : paullusi and Ae. galloisi are different from that of 24.6,dt:5,P<0.001). Ae. scutellaris, as well as from those of Ae. riversi Figure 6 shows that a maxilla of Ae. pseudoal- and Ae. flavopictus. The latter 2 species are differ- bolineatus is the shortest and it is significantly dif- ent also from Ae. pseudoalbolineatus (the alboli- f-erent from those of all the other species. Within neatus group). Within Ae. aegypti, the Makassar the scutellaris group (except Ae. albopictus), the strain is clearly different from other strains, where- maxillae of Ae. paullusi are significantly longer as strains of Ae. albopictus do not vary appreciably than those of the other species. Intraspecific varia- (conf,dence interval bars almost overlap). tion within Ae. albopictus and Ae. aegypti is con- Maxillae and mandibles show wide variation in siderable, and some strains of Ae. albopictus, as their lengths even within each strain. Examples are well as some strains of Ae. aegyptl, are significantly the maxillae of Ae. aegypri from Timor and the difl'erent from the other species, but some are not. mandibles of Ae. albopictus tiom Makassar. Note Among strains within the same species, at least the that in the Makassar strain of Ae. albopictus, 2 un- Matsumoto strain of Ae. albopictu.r apparently is usual mandible lengths occur: 0.41 and 0.45 of the diff'erent fiom the Mambi strain, and the Jakarta proboscis lengths, which exceed the length of max- and Polewali strains of Ae. aegypti are different illae (0.25 of the proboscis lengths in both cases) from the Timor strain. in their pairs. These are unique because in all other The mandibles are shorter than maxillae, with a specimens, maxillae are longer than mandibles. We range of O.O44.ll of the proboscis lengths, except eliminated the possibility of confusing maxillae as tbr 2 individuals mentioned below- Mandibles, as mandibles and vice versa by careful examination of maxillae, vary among all the strains examined (ll their bases. JounNnr- oF THE AMERTcANMoseurro CoNrr.or- AssocrnrroN Vor. 18,No.2

o 0.4J o 041 r:0.675, p<0.01 T TI R E0r* Trl rl o Itryf;[fi*;;+**o+*fl

Maxilla Fig. 8. Correlation between lengths of maxillae and EEE€€g€g3aEiisiSsmanditrles of male Stegomyia. Proboscis length : 1O0. iiS"$:i;:E?.=;E sgY.*gi$g55i Aedes aegypti is known as a highly variable species (Mattingly 1957, Christophers 1960, Huang 1979). ;= The absence of mandibles previously reported for Fig. 7. Variation of mandibular lengthsof male .Srega- Ae. aegypti possibly is due to intraspecific varia- myia. For explanation of symbols, see Figure 6. tion. We examined 5 strains of Ae. aegypti, includ- ing those from different parts of Indonesia (Makas- sar, Jakarta, Timor, and Polewali). All of them had A significant positive correlation was found be- mandibles. Furthet mandibles were found in 7 oth- tween maxillary and mandibular lengths (Spear- er species of Stegomyia examined. The presence of man's rank correlation r = 0.675, P < 0.01), as mandibles is more likely is characteristic of Stego- shown in Figure 8. Table 2 shows much higher co- myia maIes. Christophers (1960) and Lee (1974) efficients of variations (CVs) of mandibles (8.9- probably failed to flnd mandibles because they are 106.8) and maxillae (8.1-29.9) as compared to short and thin and may easily be overlooked. Even those of maxillary palpi (2.1-5.5). when present in live individuals, mandibles may appear to be missing in dead specimens because DISCUSSION they are hidden, broken, or have been removed with the gena. Huang (1979) reported that the maxillary palpi Lengths of maxillae and mandibles are highly of males of the subgenus Stegomyia are more than variable within the subgenus Stegomyia. Variation 0.50 length of the proboscis, whereas Tanaka et al. (1979) reported that they are 0.80-1.10 lengths of the proboscis for Japanese and Korean species in Table 2. Coefficients of variation for mouthpartsof the aegypti and scutellarls groups. We found that male Stegomyia. maxillary palpi vary from 0.52 to I . 19 of proboscis Species (strain) Mandible Maxilla Palp lengths for 8 species belonging to 3 species groups. As stated by Huang (1978a), maxillary palpi of the Aedes aegypti (Makassar) 19.7 29.O 5.1 males of Ae. pseudoalbolineatus are shorter than Ae. aegypti (Liverpool) 1'1.6 22.9 2.1 the proboscis. We found that they ranged from 0.52 Ae. aegypti (Jakarta) 13.3 13.7 2.6 to 0.60 proboscis lengths. Maxillary palpi of Aedes Ae. aegypti (Timor) 23.7 21.3 2.8 (Polewali) 13.6 8.1 2.1 laffooni Knight and Rozeboom, Aedes impatibilis Ae. aegypti Aedes albopictus (Matsumoto) 15.9 9.4 3.1 (Walker), and Aedes hoogstraali Knight and Roze- Ae. albopictus (Polewali) 8.9 8.9 J. t boom, all of which belong rc rhe albolineatus gro.op Ae. albopictus (Tanegashima) 19.9 15.1 2.8 (Huang 1978a, 1978b), are also distinctly shorter Ae. albopictus (Makassar) 106.8 r1.7 1.8 than the proboscis. This probably is a characteristic Ae. albopictus (Okinawa) 17.9 11.0 2.O of males of the albolineatus grolup. Maxillary palpi Ae. albopictus (Mambi) 16.4 16.4 5.5 of other species examined are as long as the pro- Aedes paullusi 9.2 I 1.5 2.1 boscis. Aedes scutellaris 36.6 I 1.6 2.7 A1l the species and strains, including 5 Ae. ae- Aedes riversi 16.2 9.4 2.9 Aedes 22.1 13.0 3.9 gypti strains, were found to have mandibles. This frdvopictus Aedes galloisi 14.9 29.9 3.4 previous by contrasts with reports on Ae. aegypti Aedes pseudoalbolineatus 16.3 9.4 5.2 Christophers (1960) and Lee (1974), who stated Average 22.9 14.8 3.2 that mandibles do not exist in males of this species. JUNB 2002 MOUTHPARTSor Mer-r AEDES(STEGoMra) MoseurroEs 79

exists even among strains within the same species ing on nutrition and density conditions. Even for (Ae. aegypti and Ae. albopictus). If multiple strains wild specimens exposed to diverse nutrition, den- are examined for other species, similar intraspecific sity, and temperature conditions during larval de- variation, as it Ae. aegypti and Ae. albopictus, velopment, CV values for body size were usually might also be found. Despite this variation, the less than 20.0 for mosquitoes breeding in ground lengths of maxillae and mandibles of the subgenus pools (Fish 1985). Thus, high variability of maxil- Stegomyia have distinct ranges (maxillae: 0. 13- lae and mandibles of male mosquitoes supports an 0.50, mandibles: 0.04-0.17, excluding 2 unusual explanation that they existjust as functionless, ves- values). These ranges may be regarded as subge- tigial structures (Downes 1970). neric attributes, although species of the edwardsi The positive correlation that occurs between and w-albus groups in the Oriental Region (Huang maxillary and mandibular lengths indicates the si- 1979) and species groups of Africa (Huang 1990) multaneous reduction of both organs in males. The have not been examined. fact that mandibles are usually shorter than maxil- Compared with other subgenera of the genus Ae- Iae might suggest that mandibles lost their function des examined by Marshall and Staley (1935), the earlier than did the maxillae. subgenus Stegomstia has, on average, longer max- Snodgrass (1959) stated that the hypopharynx in illae with a greater range of length (0. 13-{.50) than male mosquitoes is completely fused with the la- those of the subgenera Aedes (0.06-0.09), Finlaya bium and forms the labiohypopharynx. Christo- (0.20-0.28), and Ochlerotatus (O.2O4.28). Man- phers (1960) recognized the hypopharynx only as dibles of males of the subgenus Stegomyia (0.04- a ridge on the labium. On the other hand, Vizzi 0.17) are more variable than those of the subgenus (1953) found the hypopharynx of An. quadrima- Finlaya (0.09-0.14), whereas mandibles were not culatus to be a sclerotic plate on the labial gutter. found by these authors for subgenera Aedes and We found the hypopharynx of males of Stegomyia, Ochlerotatus. although it is not a free stylet, to be a structure According to the recent new classification of the clearly discernible from the inner wall of the labi- gents Aedes, subgenera Stegomyia and Aede,s re- um, thus retaining evidence of its free origin. This main in the genus Aedes, whereas subgenera Oc&- structure is also found in the genera Anopheles, Cu- lerotatus and Finlaya belong to the genus Ochler- lex, and Tripteroides (unpublished data), and is otatus (Reinert 2000). Following this new system, probably cofilmon to other mosquitoes as well. maxillae and mandibles of males appea,r to be at- Because the hypopharynx in female mosquitoes, tributes that do not distinguish these genera, as is together with other stylets, enters the host skin dur- also the case of maxillary palpi of males (Reinert ing bloodfeeding, the free hypopharynx clearly is 2000). correlated with their ability to suck blood. Silva and Marshall and Staley (1935) reported that maxil- Grunewald (2000) reported that the hypopharynx of lae of species of genera Orthopodomyia (O.28- male LutTomyia migonei Franca (Psychodidae) is a 0.37) and Culex (0.09-O.19), as well as their man- free stylet. Probably the earlier form of the hypo- dlbles (Orthopodomyia: 0.05-0.07, Culex: O.O5- pharynx of male nematoceran flies was a free stylet. 0.07), are also short. On the other hand, the Fusion of the hypopharynx of the male mosquito maxillae of species of the genera Culiseta (0.58- with the labium may have taken place after the an- O.94) and Anopheles (0.44-0.68), as well as their cestor of the mosquito separated from the sandfly's mandibles (Culiseta; O.O74.28, Anopheles: O.38- ancestor. 0.46) were distinctly longer. Other subgeneraof Ae- des and other genera in the Oriental Region are being examined to determine the taxonomic and ACKNOWLEDGMENTS phylogenetic significance of the mouthparts in We gratefully thank T. Takahashi and T. Tabata, males. who helped in preparing scanning electron micro- As stated by Yizzi ( 1953) for males of An. quad- scope images; I. Miyagi, who made many sugges- rimaculatus, and by Snodgrass (1959) for females tions on staining and dissection methods; Y. Egu- of Toxorhynchites, delicate, short, and irregularly chi, who provided some of the specimens from shaped maxillae and mandibles suggest the lack of laboratory colonies; and the 2 anonymous review- function, at least for piercing. Much higher CV val- ers, who gave useful comments to improve the ues of maxillae (14.8) and mandibles (22.9\ tnan manuscript. Collection of Indonesian strains was those of maxillary palpi (3.21 strengthen this view. supported by Grant-in-Aid for Monbusho Interna- Structures with function naturally are less variable tional Scientific Research Program (Field Research) than those without function, because they need to (1004 1200). hold a flxed shape or size to carry out their func- tion. For example, CV values calculated from the data of wing, hind femur, and scutum lengths of REFERENCES CTTED female Ae. albopictus in t}le laboratory (Mori 1929, Benjamini Y. 1988. Opening the box of a boxplot. Az Thbles 5-7, 12-14) remain usually less than 5.0, Snr 42:257-262. although the absolute lengths vary greatly depend- ChristophersSR. 1960. Aedes aegypti (L.) the yellow fe- 80 JounNlr- oF THE AMERICIN Moseurro CoNtnol Assocr,qrror Vor-. 18, No. 2

ver mosquitoes Cambridge, United Kingdom: Cam- ferences in the mouthparts of male mosquitoes. Bzll bridge University Press. Entomol Res 26:53 l-532. Cfements AN. 1992. The biology of mosquitoes Volume Mattingly PE 1957. Genetical aspectsoftheAedes aegypti 1. London, United Kingdom: Chapman & Hall. problem. Ann Trop Med Parasitol 51:392-408. Downes JA. 1970. The ecology of blood sucking Diptera: McGill R, Larsen WA, Tukey JW. 1978. Variations of box an evolutionary perspective. In: Fallis AM, ed. Ecology plots. Arn Stat 32:12-16. and physiology of parasites Toronto, Ontario, Canada: Mori A. 1979. Effects of larval density and nutrition on University of Toronto Press. p 232-238. some attributes of immature and adrlJtAedes albopictus. Fish D. 1985. An analysis of adult size variation within Trop Med 21:85-103. Reinert JE 2000. New classification for the composite ge- natural mosquito populations. In: Lounibus LP, Rey JR, us Aed.es (Diptera: Culicidae: Aedini), elevation of Frank JH, eds. Ecology of mosquitoes Vero Beach, FL: subgenus Ochlerotatus to generic rank, reclassification Florida Medical Entomology Laboratory. p 419-43O. of the other subgenera, and notes on certain subgenera Foster WA. 1995. Mosquito sugar feeding and reproduc- and species. J Am Mosq Control Assoc l6:175-188. tive energetics. Annu Rev Entumol 4O:443-474. Schlein X Muller G. 1995. Assessment of plant tissue Harbach RE, Knight KL. 1980. gktssary Taxonomist's of feeding by sand flies (Diptera: Psychodidae) and mos- mosquito anatomy Marlton, NJ: Plexus Publishing, Inc. quitoes (Diptera: Culicidae). J Med Entomol 32:882- Huang YM. 1978a. Taxonomic status of Aedes (Stego- 887. myia) laJfooni Knight and Rozeboom with redescription Silva OS, Grunewald J. 2000. Comparative study of the of Aedes (Stegomyia) pseudoalbolineatus Brug (Dip- mouthparts of males and females of Lutlomyia migonei tera: Culicidae). Mosq Syst 10:351-364. (Diptera: Psychodidae) by scanning electron microsco- Huang YM. 1978b. The identity of two species of Stego- py. J Med Entomol 37:748-753. nyia belonging to the Aedes albolineatus group (Dip- Snodgrass RE. 1959. The anatomical li.fe of the mosqui- tera: Culicidae). Mosq Sy.st l0:197-210. loes Smithsonian Miscellaneous Collections 139 No 8. Huang YM. 1979. Medical entomology studies-Xl. The Washington, DC: Smithsonian Institution. subgenus Stegomyia of Aedes in the Oriental Region Sokal RR, Rohlf FJ. 1995. Biometry: the principles and with keys to the species (Diptera: Culicidae). Contrib practice of stcttistics in biological research 3rd ed. New Am Entomol Inst (Ann Arbor) 15(.6):l-79. York, NY: WH Freeman and Co. Huang YM. 1990. The subgenus Stegomyia of Aedes rn Tanaka K, Mizusawa K, Saugstad ES. 1979. A revision the Afiotropical Region l. The africanus group of spe- of the adult and larval mosquitoes in Japan (including cies (Diptera: Culicidae). Contrib Am Entomol Inst the Ryukyu Archipelago and the Ogasawara Islands) and Korea (Diptera: Am (Ann Arbor) 26(l): l-90. Culicidae). Contrib Entomol Inst (Ann Arbor) 16:.l-987. Jobling B. 198'/. Anatomical drawing of biting.flies Lon- Yizzi FF. 1953. The mouthparts of the male mosquitoes don, United Kingdom: British Museum (Natural His- Anopheles quadrimaculatus Say. Ann Entomol Soc Am tory). 46:496-5O4. Lee R. I974. Structure and function of the fascicular sty- Wepster JB. 1954. Synopsis of a hundred common non lets and the labral and cibarial sense organ of male and anopheline mosquitoes oJ the Greater and Lesser Sun- f'emale of Aedes aegypti (L.) (Diptera: Culicidae). das, the Moluccas and New Guinea. Royal Tropical In- Quaest Entomol 10:187-215. stitute of Amsterdam Special Publication CXI. Amster- Marshall JE Staley J. 1935. Generic and subgeneric dif- dam, The Netherlands: Elsevier Publishing Co.