head is oblong, about 0.65 as broad as long; pattern distinct. The dark spot 

 in the posterior part of the frontoclypeus of the same form as in Rh.nu- 

 bila, with straight anterior margin and truncated anterior angles, situated 

 posterior to the frontal setae; the curved row of 4 or 5 dots is not always 

 distinct; the posterior angle of the sclerite is light. Dorsal stripes on the 

 head brown or dark brown, as in Rh. nubila; they are short and usually 

 extend only to the bifurcation of the epicranial suture; they are fused with 

 the lateral stripes into a large and more or less uniformly dark spot with 

 a small light spot at the base of seta 16; seta 15 situated near the anterior 

 margin of the spot, on a light background, in the notch between the stripes; 

 dots on the stripes indistinct; the broad space lateral to the coronal suture 

 usually remains light as in R h. n u b i 1 a; more rarely, relatively distinct 

 rows of dots are perceived along coronal sutures in dark specimens. 



Dorsal sclerite of labrum whitish yellow. 



The large setae on head and labrum are blackish and thick. 



Pronotum light in its anterior part and in the greater part of the lateral 

 part with indistinct pinkish brown, curved stripes on the sides; the 

 trapezoidal, broad dark figure in the posterior part is brownish, with 

 indistinct dots along the median suture and more distinct groups of dots on 

 the sides. The brown cross stripes in the broad parts of the black posterior 

 margin of the sclerite are narrower than in Rh. nubila; they are some- 

 times incomplete, not reaching the anterior or posterior margin of the 

 border; lateral margin as in R h. n u b i 1 a and Rh. septentrionis; it is 

 broadly black in the posterior part; there is a narrow dark stripe which 

 extends also to the anterior angle of the sclerite. The large setae darker 

 and stronger than in Rh. nubila. 



The sides of the anterior part of the dorsal sclerite of abdominal 

 segment 9 have a broad black margin which is narrower in the middle; 

 this dorsal sclerite is sometimes brownish or interrupted; a chestnut- 

 brown, triangular spot which does not reach the apex of the posterior margin 

 and bears reddish brown stripes on the sides on a convex part in the middle; 

 only these oblique stripes are present in light specimens; the black dashes 

 on the lobes of the posterior margin are narrow; the other parts of the 

 sclerite are whitish yellow. 



Both spinules in the distal part of the claw of the anal legs are relatively 

 large. 



Mode of life and habitats. Mountain brooks and rivulets with 

 cool water. 



Distribution. Greater and Lesser Caucasus, Iran. 



6. Rhyacophila dorsalis Curtis 



Hickin, 1942:14-16, Figures 1-10; 1954:60-61, Figures 3, a, 4, a, 5, a. - 

 Marlier, 1953b:l-3, Figures 1-4. - Mackereth, 1954:147-152, Figures 1, D, 

 2, D, 3, D. 



225 Full-grown larva. This species closely resembles Rh. nubila Zett. 

 in size, coloration and other characters. Ground color of head (Figure 214) 

 light yellow; triangular spot in posterior part of frontal sclerite dark; 

 unlike in Rh. nub i la, this spot covers posterior angle of sclerite, and bears a 



234 



