THE NATURAL HISTORY OF BOMBAY MALARIA 405 



Let us return for a moment to the head of the laroe. If we 

 examine it under the frd inch objective we shall see that it 

 possesses a sort of blunted cone-shaped forehead or clypeus, below 

 the angles of which project the feeding brushes which have very 

 much the appearance of shaving brushes. From the upper surface 

 of the forehead or clypeus just between the feeding brushes we can 

 note certain spines or hairs projecting. A pair of long hairs and a 

 pair of shorter ones can usually be distinguished. Now these hairs 

 differ in character in different species of anopheles larva? and in 

 examining such larvas we should always take special note of them. 

 In order to differentiate larvee in this way we must make use of 

 a higher power objective than frd inch. With a *th inch objec- 

 tive we can note the following differences in the leaflets of the pal- 

 mate hairs on fans on the abdominal segments and the frontal or 

 clypeal hairs respectively observable in the larvas of species of 

 anopheles mosquitoes to be found in Bombay. 



M. rossi. 

 Place the larvse in a drop of water on a slide, cover with a 

 cover glass and examine with a frd inch objective. Find 

 the frontal hairs and then use a Jtli inch objective. Note 

 two pairs of frontal hairs, a longer pair placed internally 

 with a shorter hair on each side external to these. Focus 

 very carefully and note that there is no lateral branching 

 of these hairs. 



Palmate hairs or fans.— Replace the 2-3rd inch objective 

 and move the specimen until one of the palmate hairs 

 or fans is in view, then focus with the l-6th inch objective. 

 Note that the fan is made up of a number of finely taper- 

 ed leaflets joined at the base to a common arm which 

 is attached to the upper surface of the abdominal segment, 

 In M. rossi each separate leaflet is usually very finely taper- 

 ed and extended into a long spine or filament which is as 

 long as the broader body of the leaflet. 



N. stephensi. 

 Examine the larvas in the same way but note that :— 

 Frontal Hairs.— Though at first sight closely resem- 



