Sheath of male genitalia lobe-shaped, narrow apically. 



Case 8— 10 mm long, its anterior dorsal end projecting so that the anterior 

 opening is directed ventrally, anterior membrane with a narrow, slitlike, 

 slightly curved hole near anterior margin; posterior membrane with roimd 

 or slightly widened hole at dorsal wall, membrane convex basally, cup- 

 shaped, the hole directed upward; anterior membranous end of case directed 

 to substrate, attached by several ligaments; posterior end slightly raised 

 (about 1 mm), attached by a disk on a stalk. 



Mode of life and habitats. Usually running water; large rivers 

 (Volga, Oka, Kama, Dnepr, Yenisei, Angara, and Amur); also oligotrophic and 

 mesotrophic lakes (Onega, Ladoga, Segozero, Valdai Hill); large lakes in 

 455 Latvia (Dridza, Sivers), and others; usually in open lake littoral with 

 moderate surf; on stones, on solid bottom of sand with stones or 

 stones with detritus, snags, solid bottom in areas with open vegetation; in 

 rivers with slow current on stony or sandy- stony bottom. 



Distribution. The European USSR, Siberia, the Amur region, 

 and Chukchee National District. In addition, Europe, Japan, North America. 



6. Athripsodes fulvus Rambur 



Struck, 1899:341—342. Figure 28; 1900:26, Figure 39.— Siltala, 1905:48—53, 

 Figure 11; 1907:463—465, 468—469.— Ulmer, 1909:247, 309, Figure 454 a.— 

 Lestage, 1921:606—616, Figures 203—205.— Lepneva, 1940:210. 



Full-grown larva. Length 9—11 mm. Head (Figure 732, A) wide, curved 

 laterally; gula cup- shaped, wider than in A. annulic o-r n i s . Frontoclypeus 

 uniformly reddish brown, sometimes with 4 light dots anteriorly; band in 

 posterior part formed by 4 small, narrow, transverse, dark brown dots, 

 poorly visible on the dark background. Sides of frontoclypeus with similar, 

 distinct, dark brown dots near frontal sutures; white adfrontal stripes 

 replaced by a wide, white space dividing dark median area from lateral 

 area, which extends from light yellowish periocular area to occipital 

 foramen; dark dots on white background lateral to coronal suture and fork of 

 frontal sutures. Ventral surface (Figure 732, B) white in the middle, brown 

 anteriorly lateral to gula, reddish brown, with large, dark dots near occipital 

 foramen. Gula dark brown. Setae strong, black or dark brown; chaetotaxy 

 as in species of the excisus group. 



Labrum (Figure 732, C) brownish; setae 1 and 2 sometimes branched, 

 spine-shaped, curved to the margin; seta 5 longer than others. Mandibles 

 short, with small, blunt teeth; both mandibles with 2 teeth on each blade, one 

 ventral tooth sometimes indistinct. Submentum pale yellowish, in form of a 

 thin, indistinct, slightly tuberculate plate with concave anterior margin; 

 large, yellowish brown setae on anterior-angle processes. Stipes yellowish, 

 setae as on submentum, situated laterally and at distal margin. 



Pronotum (Figure 733, A) whitish, with narrow, reddish brown, anterior 

 median margin; posterior submarginal area with reddish brown areas with 

 indistinct dots laterally. Mesonotum (Figure 733, B) thin, light, distinct, 

 with a brownish stripe along median suture, dark brown spots at anterior 

 margin, and 2—3 dots posteriorly; black, bracketlike, posterior-angle streaks 

 narrow, long; anterior-margin setae situated lateral to stripe, black, 

 moderately long; medioanal setae similar; 2 short, dark setae anteriorly 



570 



