Wile MATERIALS FOR A SURVEY «OF THE 
WOCOUITOERS: OF CALE CUTIES 
By C. A. Parva, Assistant, Indian Museum. 
[Norr.—The delay in the appearance of this paper is due to 
the fact that owing to the absence during almost the whole 
time of the survey as wellas for many years previously, of any 
scientific officer who could devote more than a small part of his 
time to the supervision of the conservation of our extensive 
entomological collections, Mr. Paiva has been unable to devote 
more than a fraction of his time to mosquito work. For the 
same reason the survey cannot be regarded as exhaustive, or 
even sufficient for the ‘‘ fringe area’’ to which it was con- 
fined, since the methods employed were rough and ready in 
the extreme. Their chief defects lie in the lack of adequate 
supervision over the collectors, and in the identification by means 
of the adults only of the larvae and pupae obtained. With 
regard to the first of these defects, Mr. Paiva tells me that it was 
easy to keep a check on the truth of the collectors’ statements as 
to the nature of the breeding-places from which different collec- 
tions of larvae were brought in, as he quickly found that some 
species preferred one sort and others preferred others, a fact 
which could not be taken into account by an ignorant collector 
anxious to avoid any suspicion that he neglected filthy water. 
But he was quite unable either to see that every type of breeding- 
place found was regularly sampled or to instruct the collectors 
personally in the art of finding larvae in large areas of water over 
which they might be dispersed ; and it is probably on this account 
that no species known to transmit malaria has been revealed in 
the collections made either by the corporation kerosening-coolies 
or by the collectors subsequently employed by the Museum ; for 
it is well known that these mosquitoes breed in clean water. With 
regard to the second defect mentioned above, it may be pointed out 
that just as different species of wild animals differ in their ability to 
thrive in captivity so some species of mosquito develop in captivity 
more readily than others, and although identifications ought to be 
checked by rearing up the larvae, they ought always, in the first 
instance, to be based on the larvae and pupae themselves ; for 
otherwise there is a danger that some species may be completely 
overlooked owing to their inability to develop under the conditions 
to which they are subjected. To have done this, however, it would 
have been necessary for Mr. Paiva to devote the whole of his time 
to the work at the actual time when the survey was in progress, and 
this it was impossible for him to do; in addition to which, at the 
