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and on the outer side. Outer appendages of male pupae extending farther 

 posteriorly than the short, apically rounded penis sheath; segment 7 of 

 female pupae with blunt, conical, ventral process. 



Pupae lying in cocoons of loose grayish tissue; case with a thick 

 covering of fine sand grains; pupal case attached to the same substrate as 

 the capturing nets of the larvae; they are sometimes completely covered 

 by the remains of the larval nets; they are dark brown because of the 

 detritus accumulated in the nets. 



Mode of life and habitats. Larvae predators; they build 

 capturing nets in form of funnels with a widely open entrance and a curved, 

 narrow end. They prefer rivers and rivulets in the plains with a 

 moderately strong current and dense plant thickets; they often occur in 

 large colonies, attaching their capturing net to plants or to the bottom; 

 they live near the banks in large rivers or in deeper places among sunken 

 branches or pieces of wood. They sometimes occur in large numbers in 

 streams between lakes; they become well adapted to conditions in reservoirs 

 when there is a rapid current; they were found in large numbers in the 

 Tsimlyansk reservoir. 



Distribution. The whole of the European USSR, Middle Asia (Amu- 

 Darya), Siberia, Kamchatka. In addition, Europe, North America (rare). 



IX. Family ARCTOPSYCHIDAE Martynov 



Full-grown larva. Length 18— 20 mm. Head oblong, dor soventr ally 

 compressed. Frontoclypeus with deep, lateral indentations and broad 

 anterior margin; clypangulus small, dark, clearly differentiated. Fronto- 

 clypeus with a broad dark figure in the middle. Gula fused with pregula, 

 oblong-wedge shaped, extending on the whole head to the occipital foramen. 

 Dorsal stripes broad, dark, distinct; dots numerous. 



Chaetotaxy of head and body of the larvae of Arctopsychidae (like that 

 of Hydropsychidae) characterized by a rich, highly differentiated secondary 

 chaetotaxy while spines are little developed. The setae of both families 

 are divided into three groups: l) primary setae, which are usually short, thin 

 and pale; 2) ordinary secondary setae, which are numerous, of different form 

 and size; they are longer than the primary setae in some places (anal legs); 

 3) small secondary setae of the covering tyoe, which differ markedly in size 

 and form; unlike the ordinary secondary setae, these small covering setae 

 are often called chetae; details on these setae are given in the descriptions. 



Head sclerites, especially in dark areas, covered with short, thin curved 

 setae. Primary setae short or moderately long; the longest setae straight, 

 blackish and strong; secondary setae present near anterior margin of head 

 in addition to primary setae. 



Labrum with similar small covering setae as on the head; anterior half, 

 middle and posterior part of labrum with numerous thick, black setae among 

 which the primary setae are indistinguishable; tufts of light brown stiff hairs 

 near the lateral margin, which are broad and pectinate. Mandibles massive, 

 long, their teeth large; chetoids of the median brush of the left mandible 

 short; outer side of mandibles with numerous secondary setae. 



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