Pupa. Spindle-shaped. Antennae thick, with short segments, not reaching 

 end of body. Maxillary palps 5 -segmented. Number of spurs on legs 

 3,4,4. Last body segment with 2 short lobes which have numerous dark 

 strong setae. 



Pupae lying in cocoons of loose tissue enclosed in a cavelike case; case 

 covered with sand grains or small stones. 



Only the larvae of Polycentropodinae of the two subfamilies recorded from 

 the USSR are known. 



Mode of life and habitats. Mainly in running water of various 

 types; some species occur in lakes and in clean, small stagnant water bodies. 



Distribution. Throughout the USSR; cosmopolitan. 



Subfamily POLYCENTROPODINAE Ulmer 



Full-grown larva. Length 10—22 mm. Head dorsoventrally flattened; 

 eyes situated near the anterior margin, sometimes very small; antennae 

 situated at the margin of the head, with one long and 2 short setae. Fronto- 

 clypeus with broad anterior margin; sides of margin with distinct clypan- 

 gulus. Gular suture long. Labrum rounded laterally, with a shallow median 

 indentation. 



Mandibles long, flattened anteriorly, with pointed, well-marked teeth; 

 median brush of left mandible small, consisting of long stiff hairs. Sub- 

 mentum complete, without median suture. Maxillary palps thin; third 

 segment much longer than 1st and 2nd segments together; galea narrow, 

 long, slightly conical. Labial lobe also narrow, prolonged anteriorly; labial 

 palps thin, well developed. 



Pronotum convex, compressed posteriorly, with a deep groove; posterior 

 angles of sclerite long, extending to the ventral side. 



Propleuron with well -developed episternum and epimeron; process of 

 trochantin conical; epimeron in form of a narrow plate, curved ventrally, 

 where it extends parallel to the posterior-angle process of the pronotum. 

 Legs with long coxae and femora, with few secondary setae; forelegs 

 shorter than midlegs and hind legs; claws narrow, slightly curved. 



Meso- and metathorax and abdominal segments with a delicate pattern 

 of white stripes and spots; the thin anterior-angle setae, medioanal setae 

 and one of the ventral setae of these segments relatively long; sides of 

 abdominal segments (as in larvae of E cnomus) with a row of thin long 

 secondary setae. Section "a" of the anal legs with a transverse constriction; 

 section "b" and sometimes also section "a" with numerous secondary setae; 

 claws narrow and long, slightly curved at the end. 



Pupa. Length 10— 13 mm. Head broad. Labrum short, with rounded 

 anterior margin and a small uniformly broad median process; 3 of the 

 dorsal setae long. Mandibles thin, sickle-shaped, without teeth, with massive 

 base; outer setae near base short, of the same length. Wing sheaths short; 

 natatorial setae of mid-tarsi light and delicate; mid-tibiae and tarsi of 

 females slightly broadened; claws of legs distinct. Plates of holding 

 apparatus small, presegmental plates present on segments 3—8, post- 

 segmental plates on segment 5. Segments 2 — 7 with thin, long, filiform gills; 



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