1. Genus Chaetopteryx Stephens 



Mode of life and habitats. Snnall brooks and rivulets, including 

 spring-fed brooks; limnocrene springs; open shore of lakes, usually near 

 river mouths. 



Distribution. Northern, western, and central parts of the European 

 USSR. In addition, Europe. 



Key to Species 

 Full-grown larva 



1 (2). Head light brown or brown; frontoclypeus darker anteriorly and in 



middle than posteriorly; dorsal stripes of head little differentiated, 

 with large dark dots; pronotum yellowish brown, middle of groove 

 in anterior third of pronotum markedly dark; tergite of segment 9 

 with sharp dots at anterior margin .... 2. Ch. villosa Fabr. (p. 379) 



2 (1). Greater part of head uniformly brown; frontoclypeus darker in 



middle; large, dark dots on area of dorsal stripes; pi^onotum brown, 

 groove in anterior third slightly darker in middle; tergite of 



segment 9 with indistinct dots at anterior margin 



1. Ch. sahlbergi McL. (p. 374) 



298 1. Chaetopteryx sahlbergi McLachlan 



Lepneva, 1928:77-79; 1940:216. 



Full-grown larva. Length 13— 15 mm. Head (Figure 524, A) uniformly 

 brown; frontoclypeus slightly darker near tentorial pits; anterior part with 

 an oblique row of 3 dots lateral to median pit, last dot some distance from 

 first 2; another 2 dots further posteriorly; wedge-shaped pattern distinct, 

 its posterior row with larger dots. Two pale dots, one behind the other, 

 on area of dorsal bands; 2 transverse rows of 2 and 3 blackish brown, large 

 dots posterior to curvature of frontal sutures; rows and groups of large dots 

 lateral to coronal suture; a longitudinal, dense pattern of dots behind eye. 

 Ventral surface brown in middle, lighter at anterior margin, with groups of 

 dots, which are sometimes indistinct, near occipital foramen, on lighter 

 background; middle with 2 narrow, dark dots close together laterally. Gula 

 (Figure 524, B) dark, narrow, with long, sometimes blunt, posterior end. 



Setae brown, dark brown, or light. Median anterior margin seta brown, 

 moderately long, intermediate seta longer, slightly thicker, dark brown, 

 lateral seta light, curved inward; anterior-frontal seta the same, thinner; 

 middle frontal seta brown, thinner and slightly longer than intermediate 

 seta; posterior frontal seta short, light, very thin. Seta 7 resembling middle 

 frontal seta; seta 9 dark brown, long, a little thicker than intermediate 

 anterior -margin seta; seta 14 the same, longer; setae 10, 11, 13, and 16 

 short, thin; seta 10 smaller than others; seta 16 procumbent; seta 12 



299 moderately long, thin; seta 15 long, thin, markedly shorter than 9; seta 17 

 slightly larger than middle frontal seta. 



374 



