2 (3). Isolated gills present on meso- and metathorax 



2. Rh. yamanakensis Iwata (p. 251) 



237 3 (2). Gills absent 



1. Rhyacophila sp. "larva praebranchiata" Lepn., larva nova 



4 (l). Sword-shaped process not broader at the base, situated on a 



separate small sclerite between sclerites "b" and "c"; gills absent 

 3. Rh. impar Mart. 



1. Rhyacophila sp. "larva praebranchiata" Lepneva, 

 larva nova* 



Full-grown larva. (Figure 233). Length 15 mm. Sclerites light brown, 

 setae (except the small setae) dark and strong. Head short, with parallel 

 sides. Frontoclypeus with a wide grayish brown, rhomboidal figure in 

 the posterior part; dots of the transverse row distinct, blackish brown. 

 230 Dorsal stripes indistinct, reddish brown, close to the frontal and coronal 

 suture, with numerous large, dark dots; indistinct dots on the place of the 

 lateral stripes. The setae of the head are strong and black; the longest 

 setae (setae 9 and 14), and the posterior frontal seta are thick. 



Pronotum with continuous broad, black posterior margin; lateral margin 

 of the posterior third also broadly black; anterior angles with a small dark 

 spot. Two long, strong black setae in the anterior-angle notch; the third 

 seta situated anteriorly, between the two above setae; it is thin, reddish 

 brown and well marked; a dark lateral spot bears several small setae; 

 sclerite with numerous dots which are darker and more distinct in the 

 middle; they are lighter and less distinct laterally; the setae are strong, 

 black .and relatively short; the medioanal seta larger than the others, with 

 a small thin dark seta at its base; second large surface seta shorter; one 

 of the 2 setae at the lateral margin is situated on the black border, the 

 second is situated slightly more distally, on the light background. 



Mesothorax markedly larger than metathorax; dorsal setae relatively 

 large and strong; anterior -margin seta of pronotum long, as usual, and 

 longer than that of the metathorax; the anterior-angle seta of the mesonotum 

 shorter than the anterior-margin seta; the small secondary seta of the 

 metanotum near the primary anterior-angle seta is thin; the strong, black, 

 medioanal seta of the 3 posterior surface setae is longer than the others; 

 the intermediate seta is thin, dark brown, of almost the same length; a 

 small thin lateral seta slightly further posteriorly. The legs are brown; 

 most of the setae are black and strong. Thoracic gills absent, as in 

 Rh. i mp a r. 



Abdomen not dorsoventrally flattened; setae dark; the dorsal anterior- 

 margin seta small and thin; the anterior -angle seta is long from the second 

 segment onward; it is displaced on segments 7 and 8 towards the anal setae; 

 the medioanal seta longer than the anterior-angle seta; intermediate seta is 

 thin and long, as on the thoracic nota; lateral seta small but well marked. 



The sclerite of abdominal segment 9 is characteristic: it is light in the 

 middle, without a dark anterior margin; a black margin is present only at 



Eleven larvae were collected by L.K. Sibirtseva (1953—1954) in the tributaries of the Chirchik River in 

 Middle Asia. 



249 



