79 



Examination of Larvae. 



Anopheline larvae cannot be mistaken for any 

 other mosquito larvae (Fig. 21). 



1. When undisturbed they lie flat along 

 the top of the water, and on every segment 

 certain hairs (palmate hairs) actually indent the 

 surface film. Observe that when viewed in certain 

 lights from one side these identationscan be plainly 

 seen. The appearance may even be as though the 

 dorsum of the larvae projected from the water. 

 This, however, is not the case. 



This appearance is diagnostic of the Anopheline 

 larva. One species (M. turkhudi) does not, how- 

 ever, rest in this position, but after rising to the 

 surface in a horizontal position slowly sinks until 

 the tail only touches the surface. 



Anopheline larvae, which are about to turn 

 into nymphae, also sometimes tend to sink, so 

 that the head is directed obliquely downwards 

 (often seen in M. rossii). 



One species of Culex, at least (C. concolor), 

 adopts a nearly horizontal attitude. The line of 

 indentations of the surface film mentioned above 

 is not, however, seen. 



2. When disturbed, Anopheline larvae dart 

 into the water, or what is very characteristic, if 

 not greatly disturbed, they pass by a series of 

 wriggling jerks along the surface of the water. 



When moving up towards the surface, an 

 Anopheline moves in a much more irregular and 

 jerky manner than a Culex larva. This is well 

 demonstrated when living larvae in a cell are 

 projected upon the screen of the lantern. The 

 Culex larvae are seen rising by a series of regular 



