littoral is often absent or represented by isolated boulders, parts of open 

 clay coast or small sand beaches surrounded by plant thickets. Rheophilic 

 forms are absent in these lakes; among the lithophilic forms, Cy rnus 

 flavidus, Leptocerus einereus, L. fulvus, L. aterrimus and 

 Limnophilus (nigriceps and p o 1 i t u s ) occur rarely on stones and 

 on clay; Molanna angustata, Anabolia soror, Mystacides 

 azure a and Oecetis ochracea are common on sand bottoms; the 

 northern species Molanna palpata does not occur there, however. 

 A fauna of plant thickets resembling the preceding fauna predominates, 

 but it is usually not so rich. Among the Leptoceridae, Setodes tinei- 

 f ormis is common, sometimes very numerous; the most common species 

 of Phryganeidae is Agrypnia pagetana (Kachalova, 1955). 



Only isolated larvae of Trichoptera are found in dystrophic lakes. 



On the rocky shore of the open littoral of the large ultra-oligotrophic 

 Teletskoe Lake in the Altai, isolated larvae of Apatania stigmatella 

 and young larvae ofDicosmoecus palatus are found; the same 

 species are found in larger numbers on stones on the boulder-covered shore 

 or in rock screes, where large populations of Dicosmoecus palatus, 

 Asynarchus 1 app on i c u s, A n i s o gam o d e s f 1 av ip u n c t a t u s, 

 Limnophilus sibiricus and Lepidostoma hirtum occur 

 frequently in the northern part of the lake with a moderately strong surf. 

 The large, sand or pebble-covered beaches are without any macrofauna; 

 in more or less calm areas of sand and pebbles, isolated specimens of 

 species are found as they are also on stones, i. e., Apatania stigmatel- 

 la, Annitella obscurata and Limnophilus sibiricus. The 

 fauna of plant thickets is poor, including isolated specimens of Mystacides 

 longicornis and Limnophilus nigriceps. 



At a depth of 10— 20 m, in addition to forms which entered accidentally 

 from the littoral, larvae of the Siberian species Mystacides dentata, 

 which is a vicarious species of the European Mystacides azure a, 

 characterize the sublittoral of the Altai lakes (Lepneva, 1949:186 — 189). 



The larvae of Ap at a ni a stigmatella, Dicosmoecus palatus, 

 Anisogamodes f 1 a v ip un c t a t a, Goera sajanensis and Mysta- 

 cides dentata are the main species in the lakes of the Katun Alps . 

 Dicosmoecus palatus is represented by isolated specimens in the 

 lakes of the Chul'cha River basin; the faunas of Trichoptera in these lakes 

 consist of common Palearctic forms such as Molanna p a lp at a, which 

 is widely distributed in Siberia, and Mystacides longicornis, 

 Agrypnia obsolet a, Limnophilus nigriceps and L. stigma. 

 The fauna of Trichoptera of small mountain lakes in the vicinity of Lake 

 Teletskoe consists only of the above Palearctic species together with 

 Phryganea s t r i a t a, N e m o t au 1 i u s punctatolineatus, Limno- 

 127 philus rhombicus, L. politus, and also of the Siberian species 



Goera sajanensis (Lepneva, 1933:145-1 46, 157; 1935; 1950:123-125). 



The littoral of the open Lake Baikal and its wide inlets is inhabited by 

 species of Baicalina, Thamastes, etc., which belong to the endemic 

 tribe Baicalini Mart. (= Thamastini Schmid), and by several species of 

 Apatania which are also endemic. The upper two meters of stones 

 subjected to the action of strong breakers are little populated by Trichoptera; 

 deeper in the 2— 4 m region, larvae of Baicalina bellicosa, B. spino- 

 sa, B. thamastoides and Thamastes dipterus are abundant ; 



119 



