200 Records of flu- liKliiin Musctnii. [Vol. XIV, 



ally on the bottom and a Glossosiphonia, probably the same as that 

 taken in the Marginal Zone, is not uncommon on Taia intha. 



PoLYZOA. — The only Polyzoon seen was Hislopia lacustris, colonies 

 of which often cover living shells of Taia and Hydrohioides and grow 

 on the exposed part of the valves of Physunio. This animal also grows 

 over posts in the water. Its growth must be rapid, for it is known to 

 cover a post in a few weeks. 



Decapod Crustacea. — Caridina annandalei is very abundant among 

 weeds and we dredged several specimens of Potamon acantliicum from the 

 bottom. 



Insects.' — Adult aquatic insects are scarce in this region. At places 

 where artificial breakwaters have been made by anchoring strips of 

 floating islands a few individuals of Gerris fossarupi and G. nepalensis 

 may occasionally be seen on the surface, in the shelter of the break- 

 Waters. A Micronecta also occurs beneath floating masses of Cerato- 

 phyUuni. 



The number of insect larvae, on the other hand, is enormous, but 

 rather in individuals than in species. At the season of our visit (the 

 latter part of February and the beginning of March) vast swarms of 

 small midges, caddis-flies and may-flies issued from the water every 

 evening at dusk. They consisted mainly of three species, a small 

 Chironomid of a genus I have been unable to identify, a small may-fly 

 of the family Baetidae and a small caddis-fly of the family Lepto- 

 ceridae. All three species are able to Hve, if they survive the attacks 

 of the fish Barilius auropurpureus (which feeds extensively upon them) 

 and other enemies, for several days. By day they conceal themselves ; 

 we found them in abundance between our books and in every possible 

 corner. Fortunately none of them were blood-suckers. In spite of 

 the prodigious abundance of the midge we were unable to identify its 

 larva ; possibly it is a red " blood- worm " very like that of many 

 European species and common in mud at the bottom. The larva of the 

 caddis-fly lives in great numbers among weeds in a little horn-shaped 

 case of consolidated silk. Its feet are fringed with long hairs and it 

 swims about vigorously by means of them. The Ephemerid larva is 

 also found among weeds. It is a rather sluggish little animal of the 

 type normal in its family. Other larvae found in this region are those 

 of numerous species of dragon-flies, Agrionidae and Aeschnidae among 

 weeds and Libellulidae on the bottom. The commonest species are the 

 Agrionids Ischneura sp. and Pseudagrion vnicrocephalum. The only 

 other larva that we found at all common was that of the Chironomid 

 Polypedilum. This larva constructs a case of silk to which it affixes 

 living Protozoa {Epislylis), and lives among weeds, feeding on the 

 Protozoa and other small animals. No burrowing larvae were observed 

 except the red " blood-worms." 



Molluscs. — All the characteristic molluscs of the lake (except Taia 

 shanensis and T. clitoralis and the paludine species of the Marginal 

 Zone) are to be found in large numbers in this region. Taia intha and 

 Physunio ferrugineus are apparently endemic in it, while the widely 

 distributed Melania tuherculata and Pisidium casertamitn were not found 

 in any other part of the lake, Taia intha, Hydrohioides nassa lacustris 



