reddish brown, strong and long; the median seta 4 is very thin, light and 

 long, the ventral seta 8 is curved and transparent as in Rhyacophila 

 s. str., situated on a small tubercle; seta 7 shorter and thinner than seta 8, 

 also light and slightly curved; dorsal seta 3 and the outer seta 6 in the 

 distal part of the claw are equally long, thin and dark; both are much shorter 

 than seta 1. 



The larva of Rh. yamanakensis was briefly described from Japan 

 by Iwata (l, 1927a:205, Figures 28-30). 



Mode of lif.e and habitats. Shallow, small mountain brooks with 

 cool water and a stony bottom. 



Distribution. In the USSR: Altai. Also Japan. 



3. Rhyacophila impar Martynov 



Lepneva, 1949:162-163, Figures 1-3. 



Full-grown larva. Length 18 mm. Length of prepupa taken from the 

 case 13.1 mm. Head (Figure 240 ) relatively small; like the pronotum, it 

 is much narrower than the meso- and metathorax. Head yellow, in some 

 places yellowish brown; pattern distinct; occipital foramen with a narrow 

 dark margin. Frontoclypeus dark in the posterior part and at the sides; 

 dots of the posterior curved row light. The dark dorsal stripes along the 

 frontal sutures and along the coronal suture together with the dark margin 

 of the frontal sclerite form a V-shaped figure; dorsal stripes with large, 

 light dots; lateral stripes absent and replaced by a few indistinct dots; a 

 narrow dark stripe along the gular suture. Lateral and intermediate 

 anterior-margin setae light and small; the former are situated lateral to the 

 frontal suture; the latter are straight, strong and slightly longer; the median 

 seta is yellowish, long and recumbent. Anterior frontal seta similar, curved 

 to the sclerite; middle seta small, light; posterior frontal seta dark and 

 long. Seta 9 situated anterior to the eye, near the anterior margin; it is 

 dark and longer than the other setae of the head; the small and thin seta 11 

 is situated slightly posteriorly; seta 7 situated at the margin and shorter 

 than seta 9; seta 14 situated posterior to the eye; it is dark and almost as 

 long as seta 9; seta 12 is situated nearby; it is shorter and thinner; seta 15 

 thin and long; seta 16 situated posterior to seta 15 and much shorter; it is 

 243 light yellowish; seta 13 situated lateral to the two above setae; it is curved 

 toward the sclerite and directed inward. 



Anterior and lateral parts of labrum broadly membranous, with short 

 white hairs; anterior margin of membranous part straight; dorsal sclerite 

 golden yellow, with a shallow median notch at the anterior margin; posterior- 

 angle sclerites reddish. Seta 1 relatively long and transparent, slightly 

 yellowish, curved inward, situated at the membranous margin; seta 4 also 

 transparent and straight, situated lateral to the medial depression of the 

 sclerite; seta 2 situated near the anterior margin; seta 5 situated laterally, 

 in the anterior -angle part of the sclerite; both setae brown, strong and 

 relatively long; seta 3 situated posterior to seta 5, transparent, thin and 

 recumbent; seta 6 situated more medially, small and brown. 



Mandibles (Figure 24l) short and massive; upper blade of the mandibles 

 (like in Rhyacophila s. str.) smooth and without teeth; lower blade of 



256 



