and strong, slightly longer than the others. Mandibles reddish brown, with 

 slightly curved blackish brown end; blade as in S.griseipennis, straight 

 and serrated; outer dark basal seta longer than in S.griseipennis, 

 markedly longer than the distance from the basal margin to the seta; a 

 transparent seta near the basal seta; it is more than half as long as this 

 and not shorter as in S. griseipennis. 



Wing sheaths reaching segment 5 of the abdomen. Natatorial setae 

 situated dor sally and ventrally on segments 1—4 of mid-tarsi short and 

 light, sparse on the 4th segment; claws brownish. 



Presegmental plates present on abdominal segments 3—8; postsegmental 

 plates on segment 5. Number of spinules as follows: 111:4; IV:5; 

 V:6-5+8— 9; VI: 8— 9; VII:9; VIII:7; denticles and plates reddish brown, 

 lighter than in S.griseipennis. Sclerites of segment 8 connected by a 

 high, dark, sclerotized fold with small spinules in a comb; a lower, 

 posteriorly-curved yellowish sclerotized fold near the posterior margin of 

 the segment. A similar fold near the posterior margin of segment 8. 

 393 End of body with two long anal rods with 20—25 strong black hooklike 

 setae. Anal appendages of young pupae broad, white, curved ventrally. 

 The imaginal characters (spurs of legs, genital appendages) are distinctly 

 visible through the integument in old pupae and are reliable characters for 

 identification of the species. Pupal case (Figure 544) as in S. grisei- 

 p e nn i s. 



Mode of life and habitats. On stony bottom (mainly pebble 

 bottom) of streams and rivulets. 



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



VI. Family PSYCHOMYIIDAE Kolenati 



Full-grown larva. Length 4.5— 11.0 mm. Anterior-margin setae of 

 frontoclypeus long, situated near the angle, close to each other; median 

 frontal seta as long as posterior frontal seta. Median depression of left 

 mandible with a dense brush of chetoids; outer setae of mandible situated 

 close together, almost of the same length. Labial lobe long, ligula thin, 

 extending beyond the maxillary palps or reaching to their end; labial palps 

 absent. Only pronotum sclerotized. Meso- and metanotum broader than 

 pronotum. Setae at anterior margin of pronotum equally spaced. 



Propleuron of a characteristic form; epimeron less well developed than 

 episternum; trochantin with a dark broad leaf-shaped distal process. 



Forelegs more massive and longer than midlegs and hind legs; articular 

 process of basal margin of coxa dark brown, conical; claws curved, with a 

 process near the base of the seta. 



Anal legs moderately long; section "a" short, much smaller than 

 section "b"; 7—8 dorsal setae on section "b", concentrated near the distal 

 margin. 



Claw without a ventral comb of spinules, replaced in some species by 

 several small denticles or larger isolated spines. 



Pupa. Length 4.2— 5.5 mm. Labrum short, semicircular anteriorly with 

 5 setae concentrated near the anterior angles. Mandibles long, their median 



440 



