404 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol, XX. 



M. culicifacies usually present a short stumpy appearance, the 

 abdomen being only about twice as long as the breadth of the 

 thorax. At first sight they almost look as though the last segment 

 or so of their bodies had been cut off. The larvae of N. stepliensi 

 and M. rossi are very much alike and vary a good deal in colour 

 according to the tint of the water in which they are living. 

 M. rossi especially presents some extraordinary variations in colour, 

 sometimes being quite black, at other times bright green and in 

 certain places quite a red colour. Usually, however, it is a dirty 

 grey or earth colour. Frequently among a batch of larvae some 

 will be seen with an almost white or colourless head which gives 

 them a peculiar appearance and causes people to imagine that they 

 must belong to a different species. 



But though experience will enable us to make a good guess at 

 the species of larvae which we may find we can only make quite 

 certain either by breeding out some adult insects or else by very 

 carefully examining the larvae under the microscope with a |rd inch 

 and |th inch objective. If we can do this the following points 

 will enable us to say to what species of anopheles the larvae 

 belong : — 



If we place an anopheles larvae upon a slide in a drop of water 

 covered with a cover glass and examine it with a low power (|rd 

 inch objective) we shall note the roundish head with blackish 

 markings which often form a sort of pattern. At each side of the 

 head the antennae project forward like horns and immediately 

 in front of the head we can distinguish the feeding brushes. The 

 head of the larva is attached to the thorax which is broad and 

 solid looking and behind the thorax extends the abdomen formed 

 of eight tapering segments. Both the thorax and the abdominal 

 segments have a number of long spiny and branched hairs project- 

 ing from their surface, but if we look very closely we shall note 

 that on a number of the abdominal segments there are small 

 beautifully shaped fans which can be folded up or opened. It is 

 by the characteristic shape of the palmate leaves which form these 

 fans, together with certain peculiar hairs which are present on the 

 forehead of the larvae that we are enabled to identify the species 

 of anopheles to which they belong. 



