Mandibles (Figure 674, B) dark brown, conical, with a thin end, and club- 

 shaped, inward -curved apex; blade serrated at base of thin end; lateral 

 setae short, basodorsal seta smaller. 



Wing sheaths pointed, reaching to middle of segment 7 in male pupae, to 

 end of segment,, 6 in female. Hind tarsus with dense natatorial setae on 

 segments 1—4, more numerous on dorsal side; fore tarsus with sparse 

 setae. 

 414 Abdominal segment 1 sclerotized in its greater part from anterior 

 margin, brown, transversely ridged, with a dark brown transverse ridge, 

 and a row of small spinules. 



Presegmental plates of holding apparatus on sides of segments 3—7, small, 

 dark brown, each with a blunt, tooth-shaped process directed posteriorly; 

 postsegmental plates of segment 5 light brown, situated close together with a 

 lateral process directed anteriorly. 



Lateral line on segments 6—8, extending partly to ventral side on segment 

 8; setae brownish. Gills on segments 2—7, as in larva; filaments slightly 

 longer. 



Anal rods thin, pointed, curved, without setae (Figure 675). 



Case (Figure 676) shorter than in larva, attached to a stone in a strictly 

 determined, slightly sloping position; anterior opening closed with a round, 

 flat stone as large as width of case, and attached by a membrane with a 

 narrow slit one third or a half as long as circumference; posterior 

 opening with a smaller stone, its membrane with small slits near margin; 

 case attached to a stone by several wide ligaments from near openings. 



Mode of life and habitats. Brooks, small mountain rivulets, 

 and springs with cold water, on stones; avoids rapid current. 



Distribution. Western and southwestern parts of the European USSR, 

 especially near the Carpathians. In addition. Central and Southern Europe. 



2. Genus P s il otr e ta Banks 



Full-grown larva. Mandibles, in contrast to Odontocerum, with sharp 

 apical, and small, blunt, basal teeth. Pronotum and mesonotum with a light 

 median stripe and 2 dark, longitudinal, lateral stripes; dark stripes on 

 pronotum extending from anterior to posterior margin; stripes on 

 mesonotum to middle of tergite, where they are fused with dark posterior 

 area. Case made of sand grains, in form of a wide, slightly curved, smooth - 

 walled tube. 



Mode of life and habitats. Running water bodies. 



Distribution. USSR: Maritime Territory. In addition, Japan, 

 China, Korea, North America. 



1. Psilotreta kisoensis Iwata (P s i 1 o t r et a japonica Banks, P. 

 Kyotoensis Iwata, P. arm at a Martynov 



Iwata, 1928a: 117-118, Figures 211-212.- Lepneva, 1958: 914-919, 

 Figures 1—3. 



Larva (Stage 4). Length 8 mm. Head (Figure 677, A) slightly oblong; 

 eyes small, situated some distance from anterior margin; a longitudinal 



519 



