Stegomyia edwardsi, Barraud, Barraud, 1923

Tewari, S. C., Munirathinam, A., Venkatesh, A., Hiriyan, J. & Reuben, R., 2008, Description of the fourth-stage larva and pupa of Stegomyia edwardsi Barraud (Diptera: Culicidae), Zootaxa 1896 (1), pp. 51-57 : 51-54

Description

Larva ( Fig. 1 ). Chaetotaxy as figured and recorded in Table 1 (n=82). Head: Heavily pigmented; seta 4-C with 11–17 (12) branches, closer to 6-C than 5-C, cephalad and mesad of 6-C; 5-C long, barbed, single; 7-C barbed with 2–4 (3) branches; 10-C barbed with 2–6 (4) branches; 11-C barbed with 9–16 (11) branches; 12-C barbed with 2–8 (5) branches; 14-C barbed with 9–15 (15) branches; 15-C barbed with 2 or 3 (2) branches; 6- Mx barbed with 14–24 (14) branches; dorsomentum with 9–13 (10) teeth on either side of 4 medium tooth. Antenna: 0.38–0.45 (mean=0.41) length of head; seta 1-A single, spinelike, inserted about 0.53 from base of shaft; 2-6-A single, inserted at or near apex.

Thorax: Setae 0, 1, 3, 8, 9, 11, 14-P stellate, barbed; 2, 6, 10, 12-P barbed, always single; 1, 13, 14-M stellate, barbed; 2–5, 7, 12-M single; 1, 3, 4, 5, 8, 13-T stellate, barbed; 2, 6, 10, 12-T single. Abdomen: Seta 6-I barbed with 3 or 4 (3) branches; 7-I barbed, with 1 or 2 (1) branches; 6-II barbed, with 2–4 (3) branches; 7-II barbed with 12–18 (13) branches; 6-III–IV barbed, usually double; 7-III barbed, with 15–22 (20) branches; 1- I–VIII, 2-I–VII, 7-IV–VII, 8, 9–13-II–VII stellate, barbed; segment VIII with 13–17 (17) comb scales in single crescent-shaped row arising from a sclerotized plate, each scale with fine fringe laterally and a long median apical spine; spicules present on ventral side of all abdominal segments. Saddle: Incomplete ventrally, heavily pigmented, speculate, marginal spicules stout, long, conspicuous ( Fig. 1E ), about 0.27–0.33 (mean=0.29) length of siphon; 1-X barbed with 3–5 (4) branches; 4-X composed of 8 long setae on grid, each seta single except fourth pair (4th pair always bifid), no precratal setae; 2 unequal pairs of anal papillae, tapered, 0.80–1.15 and 0.60–0.95 length of saddle. Siphon: Heavily pigmented, speculate, acus absent, index 1.33–1.71 (mean=1.54) about 3.46 length of saddle; seta 1-S, with 3,4 (3) branches, weakly barbed, inserted at about 0.57–0.62 length (from base) of siphon; pecten on basal 0.70–0.73 of siphon, composed of 15–26 spines, of these 5–13 spines proximal to 1-S, 4–7 (4) spines distal to 1-S and unusually an additional 5–10 (7) spines out of the row, extending laterally in a line near base of 1-S, parallel to base of siphon, each spine uniformly pigmented, some spine with fine denticles.

Pupa ( Fig. 2 ). Chaetotaxy as figured and recorded in Table 2 (n=51) Cephalothorax: Seta 6-CT stout with single to 3 (1) branches, approximately same length as 7-CT; 7CT 1–3 (2) branches; 9,11-CT single. Trumpet: Moderately pigmented, short, 2.58 to 3.11 (mean=2.83) times as long as wide at the middle. Abdomen: Seta 1- I dendritic, well developed, with 13–16 (15) main branches; 3-I single, long, barbed; 1-II with 8–20 (15) branches, dendritic; 3-II, III single, long, about same length as following segment; 5-IV weakly barbed with 1–4 (2) branches; 6-VI single; 9-VII barbed with 3–7 (4) branches; 11-VII single; 9-VIII barbed with 4–8 (6) branches. Paddle: Ovoid, index 1.18–1.42 (mean=1.30), minute serrations on basal 0.21–0.36 (mean=0.25) of outer margin, margins with hair-like fringe; 1-P single, 0.41–0.54 length of paddle.

Bionomics. The immature stages of Stegomyia edwardsi were collected from tree holes, tree stumps, discarded containers and iron containers. Females were found biting humans in forest during daytime near human habitation. Immatures of St. edwardsi were collected associated with Ochlerotatus (Bruceharrisonius) greenii , Downsinomyia nivea , Lorrainea fumida , St. albopicta , St. krombeini , St. malayensis , Verrallina (Verrallina) dux , Culex (Culex) quinquefasciatus , Cx. (Culiciomyia) fragilis, Cx. (Cui.) pallidothrax, Cx. (Eumelanomyia) brevipalpis , Cx. (Lophoceraomyia) minor , Lutzia (Metalutzia) halifaxii , Orthopodomyia anopheloides , Tripteroides (Tripteroides) indicus , Uranotaenia (Pseudoficalbia) obscura , Toxorhynchites (Toxorhynchites) edwardsi and Tx. (Tox) splendens .

Material examined. A total of 334 specimens were examined from collections made 27th August to 30th October 1993 as follows; India, Andaman District , Port Blair , Sipighat, discarded containers ♂ 12, ♀ 8, Le14, Pe15; tree hole ♂ 19, ♂ G 1; ♀ 12, Le25, Pe24, 16 fourth-stage larvae, Chouldari, tree stump, ♂ 2, Le2, Pe1, iron container ♂ 1; Soil Research Centre, tree hole ♂ 1, ♀ 1, Le2, Pe2, Nicobar District , Car Nicobar, Chukchucha, tree hole ♂ 37, ♂ G1, ♀ 42, Le8, Pe8, human landing collection ♀ 1; Kamorta Island , Dering, tree hole ♂ 2; human landing collection ♀ 2; Ramjaw, human landing collection ♀ 13; Tapong, discarded containers ♂ 1, ♀ 2, Le3, Pe3; tree hole ♂ 9, ♀ 14, Le12, Pe12; human landing collection ♀ 1. Of these ♂ 2, ♂ G1, ♀ 2, Le4, Pe4, 2 fourth-stage larvae, deposited in USNM; ♂ 1, ♀ 1, Le 2, Pe 2, 1 fourth-stage larva, deposited in National Institute of Virology, Pune, India, and others in the museum of Centre for Research in Medical Entomology , Madurai, Tamil Nadu, India.

Figures

FIGURE 1. Larva of Stegomyia edwardsi. (A). Head; (B). Dorsomentum; (C). Thorax; (D). Abdomen (I–VI); (E). Abdomen (VII–X) showing saddle with marginal spines; (F). Variation in comb and pecten scales.

FIGURE 2. Pupa of Stegomyia edwardsi. (A). Cephalothorax; (B). Trumpet; (C). Male abdomen; (D). Paddle.