Mode of life and habitats. Mountain brooks originating in 



springs. 



Distribution. USSR: Transcaucasia, Trialet Range. Not recorded 

 outside the USSR. 



1. Philocrena trialetica Lepneva 



Lepneva, 1956:900-911, Figures 1—11. 



Full-grown larva. Length 18.0— 18.5 mm; body narrow and long 

 (Figure 324); the body widest in the posterior part of the abdomen, in the 

 region of segments 6 and 8; chetoids of the sclerites form short rows of 



dense groups of 3—4, rarely 5—8 setae 

 (Figure 326); the tufts of chetoids appear like 

 dark dots under low magnification. 



Head (Figure 325) short and broad; main 

 color of sclerites yellowish, dark parts 

 brownish. Frontoclypeus with a dark heart- 

 shaped figure in the posterior part, with a 

 transverse row of large light dots without 

 chetoids;* anterior part of head with two 

 large dark spots; groups of large dots at the 

 place of the dorsal and lateral stripes. 



All 3 anterior- margin setae are situated 

 close together, near anterior angles of fronto- 

 clypeus; lateral and intermediate seta short 

 and dark; median seta light, curved inward, 

 along the margin of the sclerite, longer and 

 thicker than the other two; anterior frontal 

 seta similar and recumbent; median frontal 

 seta situated near the curvature of the suture, 

 small and thin; posterior seta short and light, 

 slightly curved inward. Seta 9 situated near 

 the anterior margin of the eye, long and dark; 

 posterior to it is seta 11, which is thin and 

 relatively long; seta 7 dark and slightly longer 

 than seta 9; small light seta 10 situated lateral 

 to the eye; posterior to this seta, the similar 

 light but thick and small seta 13; farther 

 posteriorly, the thin, recumbent seta 12 and the 

 long, dark seta 14; seta 15 has an unusual form, 

 it is short, thick, light and situated near the 

 frontal suture, not posterior to seta 14 but 

 slightly anterior to it; seta 16 situated in 

 posterior part of head, light like seta 15, but 



longer; near the suture, anterior to the bifurcation, the unusually long, 

 287 curved, recumbent seta 17; a pit posterior to it. Ventral seta 8 situated 



near the anterior margin of the head, small, thick and brownish; seta 18 



similar, shorter, situated far anterior to the bifurcation of the gular suture 



(Figure 329). 



* There are no chetoids on dots and spots which indicate the place of attachment of muscles. 



FIGURE 324. Philocrena triale- 

 tica Lepn. Full-grown larva, dorsal: 

 head, thorax and abdominal segments 

 1-3 



309 



