Hind legs long, with straight, rodlike, narrow segments, including 

 trochanter (Figure 793). Coxa with 3 large, brownish spots anteriorly; 

 near base anterior basodorsal seta light, strong, moderately long, apical 

 dorsal seta slightly longer; 5—6 long, secondary setae situated at margin 

 between prim.ary setae; posterior apical dorsal seta strong, brown, 

 moderately long, situated in about the middle; anterior surface with short 

 to moderately long setae, including both primary setae; moderately long, 

 secondary setae and both primary distoventral setae situated on ventral 

 side and also subventrally in distal part. 



Trochanter slightly wider distally; anterior and posterior setae short; 

 3 — 4 short, anterior setae situated subdorsally; a row of 6 long setae 

 posteriorly which form beginning of natatorial row; anterior basoventral 

 seta strong, moderately long; apical and subapical setae spine-shaped; 

 both posterior setae situated subapically, long, situated in a row of several, 

 long, sparse secondary setae. 

 496 Dorsal side of femur with several, short, sparse secondary setae; 



primary basodorsal seta moderately long, longer than apical dorsal seta; 

 anterior and posterior setae situated at distal margin, the former sub- 

 ventrally; posterior surface with a subdorsal longitudinal row of 12—13 

 long setae forming part of natatorial row; a similar row of long setae 

 ventrally, including both primary setae. 



Tibia longer than femur, with 3 — 4 short, anterior setae dorsally; a 

 larger seta subapically; a subdorsal natatorial row of 17—18 long setae 

 posteriorly; a similar row ventrally. 



Tarsus narrower and slightly shorter than tibia, with shorter setae; 

 subdorsal area with a short strong seta anteriorly, with a subdorsal row 

 of 15 — 16 setae posteriorly; ventral row with 12—16 setae, 6 of them in 

 form of pointed light spines. 



Claw long, slightly curved, with a thin, light, basal seta. 



First abdominal segment (Figure 790) short, with wide, dorsal process; 

 a curved row of minute, brown spinules near anterior margin; lateral 

 processes displaced ventrally; disk with spines indistinct, with indistinct 

 yellowish white sclerite. 



Gills dorsally only at anterior margin of segment 2, with short, thick, 

 cylindrical filanaents, 1 or 2 on each side. Lateral line absent; pleural 

 area of segment 8 with a row of 21—23 sclerotized dots, each with 2 hairlike 

 spinules of different size. 



Posterior part of segment 9 with a strong, brown, medioanal seta laterally 

 near posterior margin; a short, thin, lateral seta nearby; small, light setae 

 between intermediate and anterior-margin setae; tergite absent. 



Anal legs (Figure 794) short; sclerite "b" white, without pattern; 4 

 large setae dorsally at distal margin: 2 of them above claw, 2 slightly more 

 basally; a short, brownish seta laterally; short, strong, spine-shaped, 

 blunt setae and small, thin setae basally at median margin; lateral groups of 

 of such setae ventrally. Sclerite "c" with a small, light seta. Claw reddish, 

 with 2 dorsal denticles, one above the other. 



Case made of secretion, in form of a straight, elongate, conical tube 

 (Figure 795). 



Mode of life and habitats. Among vegetation in stagnant and 

 slowly running waters; often in reservoirs. 



Distribution. European USSR, including Caucasus. In addition, 

 mainly Central and Southern areas of Europe. 



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