Sclerite "b" of anal legs brown, with black setae; median distal dorsal 

 seta thick, long; neighboring seta slightly shorter, lateral seta thin, 



moderately long; median margin 

 with a similar, subapical seta and 

 a small, thin, light, submarginal 

 seta further basally; ventrodistal 

 seta brown, thin; surface with 

 4 — 5 setae of different size. 



Sclerite "c" brown, with wide, 

 black, lateral margin; seta small, 

 brownish. 



Claw reddish brown, dark brown 

 apically, with a small, blunt, dorsal 

 denticle. 



Case made of coarse sand grains, 

 almost straight, slightly curved, 

 with rough, irregular surface; ventral 

 surface more or less smooth, with 

 snaaller sand grains; posterior end 

 rounded (Figure 478). 



Pupa. Length 16 mm, including 

 anal rods, 17 mm. Antennae of male 

 pupae almost reaching end of anal 

 rods. Labrum brownish dorsally; 

 anterior margin with a slight median 

 process, small, light seta 1 situated 

 near it; long, sometimes 3 instead of 

 5, hooked setae brown, on light 

 background. Both large setae of 

 anteclypeus brown, much shorter 

 than hooked setae; lateral seta small, light, thin. Mandibles reddish brown; 

 distal part with serrated blade; lateral setae dark brown, large, about the 

 same length, dorsal seta slightly longer. 



Wing sheaths reaching end of abdominal segment 4. Midlegs natatorial, 

 with golden brown setae on the tarsal segments 1 — 4 (only dorsally on 

 segment 4). Hind legs with sparse setae on tarsal segments 1 — 3. 



Dorsal process of abdominal segment 1 yellowish, with fine, transverse 

 striation; lobes of saddle-shaped, posterior margin with a few, reddish 

 brown spinules. 



Holding apparatus on segments 3 — 6; number of hooks: HI: 2 — 3; 

 IV: 3-2; V: 3-2 +12-14; VI: 2-3; VII: 3-4. 

 Gills on segments 2 — 7. 



Anal rods as in P. stellatus; basal seta of moderate length, other 

 setae smiall; apex with snmall, reddish spinules. 



Anterior and posterior end of case closed by membranes covered with 

 sand grains; holes between sand grains small or slitlike at anterior end, 

 holes at posterior end larger, usually fused into a single cross-shaped or 

 irregular opening. 



Mode of life and habitats. Small mountain brooks and rivulets; 

 Lake Kara-Kel' (Teberda); on stones. 



Distribution. USSR: Central Caucasus. Not recorded outside USSR. 



4^77 



FIGURES 47 6-478. Potamophylax excisus 

 Mart.: 



476 —fore femur, posterior; 477 — tergite of ab- 

 dominal segment 9; 478 —larval case. 



336 



