Pupal case 10— 10.2mm long, made of minute sand grains; its ends 

 rounded, and there are small openings on the case; a narrow slit which is 

 open or slightly covered with tissue ventrally; this slit is sometimes absent. 

 490 Walls of the case covered with detritus particles, which are sometimes 

 large, consisting of fragments of stalks; case attached to substrate with a 

 few filaments at the anterior and posterior end, and laterally (but not at the 

 margin of the narrow slit); case sometimes attached to a small stone 

 which forms its ventral wall, covering the ventral slit. Cases sometimes 

 attached in rows or groups in large numbers, on top of each other. 



Mode of life and habitats. Larvae predacious, building capturing 

 chambers with a net of regular quadrangular meshes across the current 

 or at an angle to the current; the larvae feed on plankton and small benthic 

 animals which fall into the net. They live in large rivers, in the plains, 

 throughout the riverbed, on the solid ground, often on large pieces of wood; 

 they fly in large numbers; recorded from the Dnieper, Volga, Oka, Kama and 

 other rivers. 



Distribution. European USSR, including the Caucasus, Western 

 Siberia, rare in Eastern Siberia. In addition, Europe, Iran, North Africa. 



2. Hydropsyche guttata Pictet* 



Lepneva, 1929:600-602, Figure 2. 



Full-grown larva. Closely related to H.ornatula; differing in the 

 pattern on the head. Frontoclypeus with a dark band with a short posterior 

 median process and a longer anterior process which is divided at the end; 

 lateral branches of process contiguous with the dark border of the sclerite 

 in some forms, so that there are 3 light spots in the anterior part; 4th spot 

 situated posterior to the band. Spots small in dark larvae, sometimes 

 indistinct, or the whole frontoclypeus dark. This is also rarely the case in 

 the dark variety of Hydropsyche ornatula. 



Mode of life and habitats. It occurs in the same places as 

 H. ornatula, usually in smaller numbers. 



Distribution. European USSR. In addition, Europe, Iran. 



3. Hydropsyche angustipennis Curtis 



Klapalek, 1888:48, Figure 17.- Ulmer, 1903:115.- Siltala, 1905:103-107, 

 Figure 23; 1907:41 3-427, 625, Plate 15, Figure 7, j, k, n. - Ulmer, 1909:236, 

 300, Figures 362, a; 438, a. - Lestage, 1921:535-543, Figure 179, a, 181, 182. - 

 Brindle, 1960d:267-270, Figures 1-9. 



Larva. Length 17— 18mm (Figure 689). Head mainly yellowish; pattern 

 smoke brown or dark brown. Frontoclyepus (Figure 690) less broad 

 posteriorly than in H. o r n at ula, with shallow lateral indentations; tentorial 

 .q pits reddish, small; anterior margin finely crenulate, with a row of fine 

 divided chetae near the margin. Sclerite with 4 light, yellow spots on the 



* The larva from the Elbe described as H. guttata Pict. (Dbhler, 1911) is that of H. ornatula McL. 

 (see Bening, 1924:287; Lepneva, 1929:600-601). 



559 



