356 Sclerite "b" of anal legs rust brown; median seta and distodorsal seta 

 grayish brown, long; lateral seta shorter and slightly thinner, moderately 

 long; median subapical seta similar, slightly smaller; ventral seta 

 moderately long, situated more lateral than usual, thin, brown. Sclerite "c" 

 yellowish brown, with reddish brown, lateral margin; seta short, thin, dark 

 brown. 



Claw (Figure 605) light brown, chestnut brown at base and apex, with a 

 dorsal denticle and 2—3 light spinules. Setae 1 and 3 situated subdor sally 

 on median side, light and thin in contrast to Goeridae and Apatania; 

 seta 3 longer than claw, thick, chestnut brown; seta 2 thin, moderately long, 

 situated dorsally above suture; seta 6 situated in distal part some distance 

 from suture, thin and moderately long, in contrast to Limnophilidae and 

 Goeridae, longer than seta 2; setae 7 and 8 situated ventrally in basal part 

 one behind the other, both light and reaching apex of claw; seta 5 thin, 

 small, larger than in Goer a (more than half as long as seta 8); seta 4 

 situated medial to 8, smaller than 4. Larval case as in Figure 606. 



Mode of life and habitats. Running water; solid bottom of 

 clear, small brooks and rivulets; near banks of large rivers; open littoral 

 of lakes, in moderate surf. 



Distribution. USSR: from the western border to the Maritime 

 Territory, from Kola Peninsula and Lower Tunguzka to the Caucasus and 

 Middle Asia. In addition, Europe. 



2. Genus Dinarthrum McLachlan 



Full-grown larva. Length 7— 9 mm. Head not as short as in Lepi- 

 dostoma hirtum; frontoclypeus narrow, oblong, with distinct punctation 

 only in posterior part; some light dots lateral to epicranial suture and on 

 ventral side transversely oblong, sometimes like a streak; setae 9, 14, and 17 

 longer and thicker than others. Middle of posterior margin of pronotum 

 with 2 large, oblong, longitudinal, light dots; posterior part of mesonotum 

 usually much lighter than anterior part; sclerites with dark, sometimes 

 black, setae. 



Case made of sand grains or sand and detritus, rarely of detritus only, 

 as in L. hi r turn. 



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



Distribution. USSR: The Caucasus, Middle Asia. In addition, Iran, 

 Pakistan. 



Key to Species 

 Full-grown larva 



1 (4). Dorsal side of head shining, rust brown; light dots lateral to epi- 



cranial suture indistinct. 



2 (3). Pronotum dark chestnut brown; mesonotum grayish brown, brownish 



posteriorly; coxae blackish brown; Caucasus 



3. D. tchaldyrense Mart. (p. 451) 



445 



