1. Subfamily HYDROPSYCHINAE Ulmer 



Full-grown larva. Length 14— 20 mm. Frontoclypeus broad, without 

 lateral indentations. Labrum short and broad; tufts of long hairs, which 

 are broadened like combs at the apex, laterally near the anterior margin. 

 Median depression of left mandible with a penicillus. Submentum 

 anteriorly with 2 broad lobes divided by a narrow median stripe. Mesonotum 

 with a black, curved spot in the middle of the posterior margin; median 

 spot at posterior margin of metanotum small, black. Trochantin of prothorax 

 479 with a basal hornlike process so that it appears forked. Claws of legs with 

 an ordinary basal seta. 



Ventral side of segments 8 and 9 with paired, yellowish, triangular 

 sclerites densely covered with thick, long setae. Anal legs relatively long; 

 sclerite "b" with a median plate with a dense tuft of numerous long setae 

 forming a fan at the apex. 



Pupa. Length 8—15 mm. Antennae as long as body or slightly shorter, 

 Labrum with numerous, short, secondary setae, mainly anteriorly, 

 Mandibles long, slightly curved; blade serrated; several denticles longer 

 than the others; outer setae situated in the basal part, numerous. 



Wing sheaths blunt, reaching abdominal segments 5 — 6. Natatorial setae 

 present on segments 1 — 3 of mid-tarsi. Presegmental plates present on 

 segments 3—7 or 3—8, postsegmental plates on segments 3—4. Gills present 

 on segments 1 — 7 or 2—8. Anal rods uniformly broad, long, with blunt or 

 forked end. 



Pupa lying in a loose cocoon; case cavelike, made of small stones or 

 large sand grains. 



Mode of life and habitats. Brooks, rivulets and rivers of various 

 types, including large rivers in the plains. 



Distribution. European and Asian parts of the USSR. In addition, 

 cosmopolitan. 



Key to Genera of Hydropsychidae 

 Full-grown larva 



1 (2). Medium sized (12— 14mm) or larger, 18— 20 mm long. Head dorsally 



with a characteristic dark lyre -shaped figure and with large, light 



spots arranged in a different manner 



1. Hydropsyche Pict. (p. 547' 



2 (l). Length 10—11 mm. Pattern present on the dark, or slightly dark, 



background of head; pattern consisting of small, light spots 



2. Cheumatopsyche Wall. (p. 581] 



Pupa 



1 (2). Length 9— 14 mm; 4th segment of maxillary palps longer than 



segments 2 and 3; postsegmental plates of abdominal segment 3 

 transverse 1. Hydropsyche Pict. (p. 547) 



2 (l). Length 6— 7 mm; 4th segment of maxillary palps shorter than 



segments 2 and 3; postsegmental plates of abdominal segment 3 

 rounded 2. Cheumatopsyche Wall. (p. 581) 



546 



