Key to Species* 

 Full-grown larva 



1 (2). Head longer than broad; anterior part of frontoclypeus slightly dark, 



rarely light; ventral side of head light, without dots. Filaments of 

 abdominal gills thick; two dorsal filaments long, with indistinct 

 secondary constrictions in the distal part; ventral filament shorter 



and thinner than the others, not differing much in color 



1. Rh. forcipulata Mart. (p. 243) 



2 (l). Head broad, short, only slightly longer than wide; anterior part of 



frontoclypeus almost completely dark; ventral side of head with 

 longitudinal groups of dark dots. Filaments of abdominal gills less 

 thick, without secondary constrictions in the distal part; ventral 

 filament of tuft shorter, thinner and markedly lighter than the other 



filaments, sometimes transparent 



2. Rh. bacurianica Lepn. (p. 246) 



1 . Rhyacophila forcipulata Martynov (Rhyacophila 

 sp.,sp.n. ? Mart.; Rhyacophila sp. "larva arthro- 

 branchia" Lepneva) 



Martynov, 192 6a: 25.- Lepneva, 1946:325-330; 1957:13; 1961:652-654. 



Full-grown larva. Length 18— 30 mm;* * sclerites light yellow; pattern 

 distinct. Head (Figure 226) slightly oblong (length to breadth = 1:1.2). 

 Frontoclypeus broader than in species of Rhyacophila s. str., with a 

 short anterior part; posterior part markedly longer than anterior part. 

 The dark figure on the posterior part of the sclerite is rhomboidal, with 

 a truncate anterior angle; posterior angle of sclerite dark; area of curved 

 row of light dots darker than the other part of the spot; the row has 2, 

 rarely 3, small light dots in the middle; there is a large dot in the form of a 

 comma at sides; two light dashes at level of posterior frontal seta, lateral 

 to the spot. Anterior part of sclerite usually light; the rhomboidal spot 

 extends anteriorly in a dark median stripe. Dorsal stripes broad and 

 smoky brown, close to epicranial suture, with longitudinal rows of dark dots; 

 lateral stripes shorter, their dots less distinct; the dark connection 

 between the stripes has a light spot at the base of seta 16; ventral side of 

 head light. 



Most large setae of the head darker and~ thicker than in Rhyacophila 

 s. str., especially in Rh. nubila and Rh. septentrionis; seta 9 longer 

 than the others; posterior frontal seta and seta 14 almost as long as seta 9; 

 setae 12, 15 and 16 shorter and also dark; seta 7 dark brown, with a long, 

 thin, lighter end; the small ventral seta 8 is brownish and much larger than 

 the very small light seta 18. 



* Two larvae of the group Pararhyacophila were described as "larva arthrobranchia" and "larva bakurianica" 

 from the Caucasus (Lepneva, 1946:325—331). It was later established from a large amount of material that the 

 "larva arthrobranchia" isthe larva of Rh. forcipulata Mart, and the "larva bakurianica" is that of 

 Rh. bakurianica Lepn. (Lepneva, 1957:13; 1961:652-658). 

 ** Full-grown larvae longer than 24mm were not found in Transcaucasia, in rivers of the Trialet Range in 

 the region of Bakurian and Borzhomi; in the streams of the Main Caucasus (Teberda, along the Voenno- 

 Georgian road) larvae of Rh. f or ci pu la t a, 25— 30mm long, are common. 



243 



