The claw is equally well developed in the basal and distal parts; distal 

 part with two blunt ventral spinules; setae 5, 6 and 8 longer than the others; 

 seta 1 strong, black; seta 2 short and thin; seta 3 moderately long, curved 

 toward the distal side; seta 8 transparent, situated on a small tubercle, 

 longer than seta 7. 



Mode of life and habitats. Mountain brooks, on stones. 



Distribution. USSR: Sakhalin, probably also in the Maritime 

 Territory. In addition: Japan. 



6. Group Prosrhyacophila Dohler 

 Dohler, 1950:272,274. 



Full-grown larva. Length 9— 14 mm; body flattened; head relatively 

 broad. Distal end of right mandible divided; basal tooth of lower blade 

 large and blunt; submentum broad, almost square. Thoracic gills absent. 

 Abdominal gills present on segments 1—8 or 2—8 in form of single finger- 

 like processes which are broader at the base. Anal legs without sword- 

 shaped process; all 8 setae of the claw long. Larvae of two species are 

 known, a European and a Siberian species; these larvae differ markedly 

 from each other. 

 250 Mode of life and habitats. Cool brooks, on stony bottom. 



Distribution. USSR: Carpathians (?), Altai, Sayans, Maritime 

 Territory. In addition: southern and Central Europe. 



Key to Species 

 Full-grown larva 



1 (2). Fingerlike gills longer than the segment; ventral tubercle at base 



of gills absent; claw of anal legs without small ventral claws. 



Europe 2. Rhyacophila laevis Pict. (p. 271) 



2 (l). Fingerlike gills shorter than segment, with a ventral tubercle at the 



base; claw of anal legs with small ventral claws. Asia 



1. Rhyacophila retracta Mart. 



1. Rhyacophila retracta Martynov 



Lepneva, 1949:166—167, Figures 11-14. 



Full-grown larva. Length 14.0— 14.2 mm; sclerotized areas reddish 

 yellow; pattern brown or blackish brown. Length of head 1.4 mm, width 

 1.2 mm (Figure 254). Frontoclypeus light, reddish brown anteriorly, the 

 dark heart-shaped figure occupies almost the whole posterior part of the 

 sclerite; it bears a curved row of four transverse dots behind the curve 

 of the frontal sutures. Laterally, anterior to the posterior frontal setae, 

 there are 3 more small, oblong light dots. Frontal setae black; the middle 

 and anterior setae are small, setuliform; the anterior seta situated some 

 distance from the margin of the sclerite, opposite the middle seta; the 



265 



