Belaya and Sylva, when they had their natural character. In other, smaller 

 tributaries of the Volga, N. b i ma cu la t a or B. subnubilus predominated. 

 Large numbers of Brachycentrus subnubilis were observed in the 

 past in many localities in the Sheksna. Neureclipsis bimaculata 

 occurs in large numbers on Potamogeton in a small tributary of the 

 Volga near Saratov (Bening, 1924:256; Lepneva, 1928b:49-51; 1929b:161-162). 



The caddis fly fauna is more diversified in the Dnieper, the largest river 

 of the southern European USSR. Before reconstruction, the stream form 

 (Hydropsyche angustipennis) occurred in rapids, and two forms 

 which occur also in rapids in Ciscaucasia: Hydroptila emarginata 

 and Psychomyia pusilla. Hydropsyche ornatula predominates 

 throughout the course of the river; large numbers also occurred in the 

 rapids of the Dnieper in the past; hundreds of larvae were found in one 

 sample from the rapids; 833 specimens were counted on the surface of a 

 stone with an area of 625 cm (Beling, 1939:19). Hydropsyche was also 

 found in large numbers further upstream, in the middle reaches of the 

 Dnieper, where 480 larvae of Hy dropsyche and 2 larvae of Neure- 

 clipsis bimaculata were collected from a small branch 22 cm long 

 (Zhadin, 1940:653). Hydropsyche guttata, Neureclipsis bima- 

 culata and Brachycentrus subnubilus occur in much smaller 

 numbers in the Dnieper; these three species were very constant in the 

 former rapids. Among the forms which also occur in lakes, Leptocerus 

 excisus, L. fulvus and L. senilis were found near the banks on stones 

 and on the bottom; Agraylea pallidula, Orthotrichia tetensii, 

 Ecnomus tenellus and Cyrnus flavidus were found in plant 

 thickets in some localities. The rheophilic fauna of caddis flies of the 

 Dnieper disappeared from the reservoir (Beling, 1939:18—38; Zhadin, 

 1940:654-664; Zhuravel', 1934:53; Lepneva, 1932:75-94). 



Two stream forms, Rhacophila nubila and Hydropsyche 

 angustipennis, were found in the Southern Bug; of the forms 

 characteristic for rivulets in Ciscaucasia, Hydroptila emarginata 

 and Psychomyia pusilla occur also in the Dnieper, and Cheuma- 

 topsyche lepida is widely distributed in the Southern Bug. The most 

 common species are Hydropsyche ornatula, Neureclipsis 

 bimaculata and Brachycentrus subnubilus. Leptocerus 

 annulicornis and L. senilis occur on the bottom near the banks; 

 Agraylea pallidula, Ecnomus tenellus, Setodes tineiformis 

 and Mystacides longicornis occur in plant thickets (Lepneva, 

 1932:75-96). 



In the rivers of the Don basin, the potamobiont species are gradually 

 replaced by phytophilic forms. In the unchanged parts of the Don, where the 

 current becomes slower and the vegetation is more developed, the potamo- 

 bionts Hydropsyche ornatula, Neureclipsis bimaculata and 

 Brachycentrus subnubilis predominate; they were previously 

 distributed throughout the river. They are mainly found on stones under 

 steep banks, where the current is 0.5—0.7 m/ sec, and in parts with a solid 

 clay bottom; Neureclipsis bimaculata and Brachycentrus 

 subnubilus were also found in the Don on sand and silt soils, where they 

 attached their cases and nets to tree trunks and shells. Leptocerus 

 fulvus occurs in some localities on the bottom near the banks; Ecnomus 



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