kelee Noon Soro Dib? of, AiR Viae tO a FOL O- 
MHeYoON GH ES TMMESE RICORS, OW © K: 
By C. A. Paiva, Assistant, Indian Museum. 
In the course of a ‘‘census”’ of the mosquitoes of Calcutta 
that is being undertaken by the Indian Museum, I have been able 
to make the following notes on the larve of Toxorhynchites 
tmmisericors, Wlik., which are very common in some parts of the 
fringe area of the town, especially in the months of June and 
July. Large numbers of the larve and pup of this species 
have been found in earthen pots. 
Mr. E. E. Green of Ceylon, in his paper on the development 
of this mosquito, on p. 161 of the Spolia Zeylanica, vol. ii (1905), 
mentions that its larva is carnivorous and feeds on the larve of 
Culex. He mentions also that the larva feeds on others of its own 
species, the largest and strongest being the only survivor. Mr. 
Green never found more than one larva at atime. The breeding 
places where he discovered these larvee were hollow stumps of the 
giant bamboo and small pools in the angles of the branches of 
other trees. Larve of Toxorhynchites have not yet been found 
in such places in Calcutta, but in earthen pots not only single 
individuals have been found, but as many as nine and ten 
together. In such cases no larve of any other mosquito have 
been found. 
As it was suspected that the larvee must have devoured those 
of Stegomyia fasctata that are usually common in earthen pots, and 
to prove that Stegomyia larve were palatable to them, on the 
16th July, 1910, a number of Stegomyia larvee were introduced 
into a bottle containing about half a dozen T. tmmisericoys larve. 
Not a minute elapsed after the former larvee were put into the 
bottle, before each 7. immisericors larva had seized one of them 
and was devouring it with apparent relish. The way the prey is 
seized seems interesting. It must first be remarked that the larve 
of T. immisericors are very sluggish and cannot swim very fast. 
Mr. Green mentions that although he watched a larva of 
T. immisericors seizing a Culex larva he was unable to see the 
exact method of catching the larva. He, however, discovered that 
the falcate lamellae, which are situated on each side of the head, 
were the organs of prehension. Each of these lamella, according 
to Mr. Green, is minutely toothed at its extremity. The mode of 
capture, as has been noticed in the specimens kept under observa- 
tion in the Indian Museum, is as follows :— 
The larvee of IT. immisericors lie quietly at the surface of the 
water, with their bodies generally in a vertical position, and the 
