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American Midland Naturalist Monograph No. 3 



ABDOMEN. (Fig. 17). — Abdominal segments I to VII bear lateral abdomi- 

 nal hairs and subdorsal and dorsal paired tufts. Segment VIII is somewhat 

 triangular in shape when seen from a lateral view and bears the siphon (air- 

 tube) postero-dorsally and three large hair tufts, the siphonal, the subsiphonal, 

 and the anal, postero-Iaterally, with smaller, usually single, hairs between them. 

 These large hair tufts are referred to by Hopkins (81) as tufts A, B, and C. 

 The eighth segment also bears bilaterally a comb composed of a row or patch 

 of tooth-like scales (absent in Megarhinini). The number, arrangement and 

 shape of the comb scales are of considerable diagnostic value. 



Extending bilaterally from the base of the siphon there is a subventral 

 longitudinal row of spines or teeth forming the pecten (absent in Megarhinus, 

 Orthopodomyia and Wyeomyia) . The siphon also bears one or more pairs of 

 subventral hair tufts (sometimes obsolete in Psorophora) . Lateral and sub- 

 dorsal tufts and a subapical spine may be present in some genera. The orifice 

 of the siphon is surrounded by five valves; an unpaired median or dorsal valve, 

 a pair of small lateral valves, and a pair of large ventral or posterior valves, 

 each of which commonly bears a single small hair. A small, sclerotized, anchor- 

 like projection, the acus, may be present at the base of the siphon. Features of 

 the siphon which are of taxonomic importance are its shape, the relationship of 



Fig. 18. Head of Culicine larva. A, preanlennal hair; B, lower head hair; C, upper 

 head hair; d, posfclypeal hair; e, sutural hair; f, trans-sutural hair; pc, preclypeal 

 spine; at, antenna! tuft; p, papilla; ss, subterminal spines; ts, terminal spines. 



