2 (l). Frontoclypeus irregularly oblong-triangular; forelegs character- 

 istically specialized, markedly different from mid- and hind legs; 

 claws very long. Distributed in Middle Asia and in the south of the 

 Ussuri Territory; rare 2. Hydrobiosinae Ulm. (p. 316) 



Pupa* 



1 (2). Length 8— 20mm; case consisting of small stones or large sand 



grains; cocoon thick, reddish brown; common throughout the USSR 

 1. Rhyacophilinae Ulm. 



2 (l). Pupae at most 7— 8 mm long. Case consisting of sand grains or 



small stones; pupa situated in a yellowish brown transparent cocoon; 

 rare 2. Hydrobiosinae Ulm. (p. 316) 



1. Subfamily RHYACOPHILINAE Ulmer 



Full-grown larva. Length 12—30 mm. Head more or less flattened, with 

 uniformly developed dorsal and ventral surface in most forms; frontoclypeus 

 with deep lateral notches in about the middle of the sclerite; tentorial pits 

 distinct and dark at bend of frontal sutures. Gula triangular, pregula broad, 

 sometimes in form of a trapezoidal sclerite. Eyes situated close to anterior 

 margin of the head; antennae situated at margin of the gnathal opening, 

 between articulation of the mandibles. Labrum with rounded anterior 

 angles; dorsal sclerite with a wide median notch anteriorly; setae, except 

 seta 1, are situated at or near the sclerite margin. Submentum forming a 

 short, broad sclerite which is usually narrower and shorter than the pregula. 



Pronotum with a broad, dark border posteriorly; secondary setae few in 

 number; meso- andmetanotum membranous; secondary setae absent except 

 for a small seta at the anterior angle which is constant in this order; they 

 are also absent on the abdominal segments. 

 210 Setae of legs also only primary; trochanters and femora ventrally with 

 a narrow membranous stripe. Gills, if present, situated at base of mid- 

 and hind legs and in pleural region of abdominal segments. Dorsal sclerite 

 of segment 9 broadly dark at anterior margin; its posterior margin notched 

 in the middle, with 4 lateral setae. Six anal gills; anal legs of different 

 structure in the different genera and groups of species; they usually have a 

 basal ventral hook on sclerite "b"; they sometimes have a long process on 

 sclerite "b" or "c"; the claw is with or without ventral spinules. Primary 

 setae may be very long or very short, slightly dark. Larvae live free, 

 without case. The species of the subfamily are predatory. 



Pupa. Length 11—22 mm. Antennae extending in male pupae to 7th or 

 8th abdominal segment; in female pupae, to middle of 5th segment; basal 

 segment larger than others, usually with 3 setae. Labrum with 5 setae. 

 Mandibles asymmetrical; left mandible with 2 teeth; right mandible with 

 3 teeth; anterior (dorsal) seta of mandibles curved and smaller than 



Pupae of Hydrobiosinae have not been found in the USSR; the pupal cases examined contained a larva 

 (prepupa); provisional identification is given on the basis of the case, cocoon and size of the pupa. 



216 



