1915J Fauna of the Chilka Lake : Aquatic Insects. 187 



Family Chironomidae. 



It is probable that several species of this family breed in the lake during the 

 freshwater season, and we have frequently seen large numbers of larval skins floating 

 on the surface of the main area at this time of year ; many species certainly breed 

 in small pools near the edge. This is probably the case with at least one blood- 

 sucking form (Culicoides peregrinus, Kieff.) very common at Barkul in July and Sep- 

 tember. 1 Immature stages of only one Chironomid were, however, taken in the lake 

 itself. 



The species belongs to the genus Palpomyia, but seems to be distinct from any of 

 those described from India. It is perhaps allied to P. polysticta, Kieffer, 2 which it re- 

 sembles in the colour of its thorax, but all the femora and tibiae are dark brown, only 

 slightly pale at the joints, while the tarsi are white with black rings at the joints and 

 with the distal segment brownish. The abdomen of the female is white below, at any 

 rate in spirit, except for the last two segments, and the dorsal surface appears to be 

 brownish with ill-defined white spots. 



Although the pupal stage, of which we give a figure (pi. xi, fig. 10) was common 

 in the Potamogeton thickets of Balugaon Bay in February and March, we did not 

 succeed in finding the larva. The fly was seen in considerable numbers on the sur- 

 face of the water and a few specimens were hatched out in an aquarium. 



Family Culicidae, 



Major A. B. Fry in reference to the Chilka Lake writes as follows 3 : — ff Villages 

 are built on the very borders of the lake, and though most of them have a few 

 patches of rice cultivation the vast perennial mosquito population comes from the 

 lake itself. In situations sufficiently protected by weeds and algae from the attacks 

 of fish, anopheline larvae and nymphs are in veritable swarms. The majority were 

 Pm. rossi and N. fuliginosus , but M. listoni were present. My second visit was to 

 look for Pm. ludlowi, in consequence of Christophers' observations in the Andaman s ; 

 but I found none, but discovered M. fowleri and M. nigerrimus ." 



Notwithstanding a careful search at many localities, the only mosquito larvae 

 we were able to find in the lake were those of Anopheles rossii, Giles, which were 

 abundant among weeds off Barkul in February and July in water of specific gravity 

 roo75 to i*oo8 and also off Nalbano in September in fresh water. The absence of 

 A . ludlowi is somewhat remarkable, as it is the common Anopheline in brackish water in 

 the neighbourhood of Calcutta. 



Major Fry's visits to the lake were made in January ; in March and September 

 we failed to find even A. rossii off Satpara, and our impression is that most of the 

 mosquitos breed in small pools of water near the edge rather than in the lake itself. 



We have to thank Major Christophers for confirming our identification of 

 A. rossii. 



1 Rec. Ind. Mus., IX, p. 246 (1913). * Rec. Ind. Mus., VI, p. 116 (1911). 



3 First Report on Malaria in Bengal, p. 35 (Bengal Secretariat, Calcutta, 1912). 



