Ig10. | C. A. Patva: Notes on Mosquito Larve. 189 
larva of 7. immusericors had taken possession of a Desvordea larva. 
They could not eat these larve as fast as they ate the Stegomvia 
larve, and although the greater portion of one Desvordea larva 
had been sucked quite dry, its head and tail wriggled about as 
if it (the Desvoidea larva) wanted to extricate itself from the 
clutches of the other larva. In most cases the Desvotdea larve 
are seized just behind the head, which renders them helpless to 
attack their enemies, as these larve, too, have been observed to 
eat other mosquito larve. 
The larve of 7. immisericors will eat any mosquito larve. 
Larvee of Culex and Mvzomyia were also put into the bowl 
together with eleven additional larve of T. immusericors in 
different stages of growth and evidently hungry, for they seized 
whatever came in their way first. One small larva of T. tmmi- 
sericors did not take more than a minute to finish.a larva of 
Myzomyia rossii. On the evening of the 20th July, Ig1o, over 
fifty larvee consisting of Culex, Desvotdea and Myzomyia were 
placed in the same bowl, with twelve larve of T. immusericors. 
By 10 A.M. of the following day there was no trace of a single 
living larva of any of the three kinds in the bowl. Moreover, a 
large larva of T. emmvsericors had also been half eaten by another 
of nearly the same size as itself. I have preserved it in this con- 
dition in alcohol, as well as another larva of T. zmmisericors in 
the act of devouring a Desvotdea larva. 
One peculiarity about the larve of JT. «mmusericors and their 
selection of their prey with regard to its size, is that if various 
sizes of larvee are placed in the receptacle in which they are, the 
larger larve of T. immisericors will first devour all the other large 
larvee of other mosquitoes, leaving the smaller ones to the last. 
The smaller larve of T. immuusericors will seize those of the smaller 
kind, but they do not hesitate to tackle a Desvotdea larva, although 
they are very slightly bigger than Desvoidea larve themselves. I 
have not yet observed a larva of T. :mmisericors devour another 
of its own kind when there is a plentiful supply of other larvee in 
the receptacle in which it is. In fact it seems to be its last 
resource when no other larve can be had. Otherwise, when the 
larvee of T. immisericors are confined to small receptacles of water, 
they will eat any kind of larve they get. They display no choice 
with regard to their food, and as they are carnivorous in habit, they 
will readily eat whatever larvee come in their way. If five or six 
specimens of this larva are put each into a pot or pan containing 
water and in which there are mosquito larve, it will be found 
that within one night all the other larve will be devoured. The 
carnivorous larvee seem to be plentiful enough round Calcutta and 
may also be found within the limits of the town itself, as adult 
specimens have been found in numbers in a garden centrally 
situated in Calcutta. 
It has been found, as is shown by these notes, that the larvee 
of T. «mmusericors feed greedily on the larvee of Stegomyia, and as 
S. fasciata, the yellow fever mosquito, is very common in earthen 
