Culiseta

Azari-Hamidian, Shahyad & Harbach, Ralf E., 2009, Keys to the adult females and fourth-instar larvae of the mosquitoes of Iran (Diptera: Culicidae), Zootaxa 2078, pp. 1-33 : 24

Key to subgenera, species, and subspecies of genus Culiseta : fourth-instar larvae

(key characters are illustrated in Figs 5 and 6 )

1. Siphon index (SI) usually less than 2.5 (1.4–2.4); antenna very short, with antennal index (ratio of length of antenna, without apical setae and appendages, to length of head) 0.3–0.4; saddle (dorsal plate) incomplete, covers abdominal segment X (anal segment) only dorsolaterally; antenna smooth; seta 1-A (antennal tuft) with 1–4 simple branches, not longer than 2.0 width of antenna; pecten spines large, distal spine near apex of siphon (pecten about 0.75 length of siphon); dorsal pair of anal papillae (gills) slightly longer than ventral pair; at least some scales of comb spiniform; setae 5,6-C (inner and median frontal setae) single [siphonal trachea broad, ribbon-like; PTF 3:1:3:6:3:1:6] (subgenus Allotheobaldia) ............................................................................. Cs. longiareolata

- SI usually more than 2.5; antennal index usually more than 0.4; saddle complete, encircling segment X; antenna spiculate; seta 1-A with more than 4 branches, longer than 2.0 width of antenna; pecten spines fine, distal spine never near apex of siphon; anal papillae of more or less equal length; all comb scales evenly fringed at sides and apex, not spine-like; setae 5,6-C multiple branched ................................................................................................ 2

2(1). Siphon index (SI) more than 4.0 (4.3–7.0); antenna very long with index 1.0 or more; seta 1-A with more than 15 (16–30) long branches, extending well beyond apex of antenna; pecten without distal filamentous spines; pecten not extending beyond basal 0.3 of siphon; antenna with distinct thick proximal and narrow distal sections; seta 5- C (inner frontal seta) with 1–4 branches; siphonal trachea narrow, rounded; seta 1-X (saddle seta) more than 0.5 length of saddle, single; 5–9 precratal setae present [PTF 1:1:2:1-2:1:1:2–3] (subgenus Culicella ) ......................... ............................................................................................................................................ Cs. morsitans (Note 39)

- SI at most 4.0; antenna short with index less than 0.7 (usually less than 0.5); seta 1-A with no more than 15 short branches, not reaching or extending only slightly beyond apex of antenna; pecten with distal filamentous spines; pecten extending beyond basal 0.3 of siphon; antenna without 2 distinct sections; seta 5-C usually with more than 4 branches; siphonal trachea broad, ribbon-like; seta 1-X about 0.5 or less length of saddle, with 2 or 3 branches; 2–5 precratal setae present (subgenus Culiseta ) (Note 38)....................................................................................... 3

3(2). Seta 4-X (ventral brush) usually with 4 (3–5) precratal setae, at least 2 perforating saddle; comb scales narrow, elongate with parallel margins; pecten extends to 0.75 length of siphon; siphon index (SI) at most 3.0 (2.7; 2.4–3.0), siphon slightly tapered apically; anal papillae (gills) bluntly rounded at apex [PTF 1:1:2–3:3–4:1:1:4–6] ( Cs. alaskaensis ) (Note 40) ...................................................................................................................................... 4

- Seta 4-X usually with 2 (2 or 3) precratal setae, 1, rarely 2, perforating saddle; comb scales short, distinctly broader at base, narrowed medially; pecten extends to 0.67 length of siphon; SI usually more than 3.0 (2.4–4.0), siphon markedly tapered apically; anal papillae tapered [PTF 1:1:3–6:3–6:1:1:3–5] (Note 41) ............................5

4(3). Seta 4-C (postclypeal seta) with 3, very rarely 4, branches; head and siphon very dark, often almost black............ ..................................................................................................................................... Cs. alaskaensis alaskaensis *

- Seta 4-C with 3–7 (usually 5 or 6) branches; head and siphon pale-brown, sometimes yellowish brown ............... ............................................................................................................................................... Cs. alaskaensis indica

5(3). Seta 4-C (postclypeal seta) inserted in line with (directly anterior) to seta 5-C (inner frontal seta) (index 0.8–1.2, average 1); head and siphon dark brown [SI 3.6–4.0] .......................................................................... Cs. annulata

- Seta 4-C inserted anteromesad of seta 5-C, i.e. closer to midline than in Cx. annulata (index 1.2–1.6, average 1.5); head and siphon pale-brown or dark ochreous [SI 3.3–3.6] .............................................................. Cs. subochrea

Figures

FIGURE 5. Characters of the head of mosquito larvae used in the keys. Dorsal and ventral aspects of a culicine larva. (Modified from Harbach & Knight, 1980).

FIGURE 6. Characters of mosquito larvae used in the keys. A, Lateral aspect (right side) of an aedine larva. B, C, Lateral aspects (left sides) of the terminal abdominal segments of a Culiseta and an Anopheles larva, respectively. (Modified from Harbach & Knight, 1980).