201 



3. When the larvae are hatched, transfer them 

 (after a day or two) to a larger vessel of fresh water 

 containing some weed. When the fresh natural 

 appearance of the water disappears, more fresh water 

 from a pool should be added. 



4. By keeping larvae in a not too porous earthen- 

 ware vessel, they may be placed with impunity all day 

 in the direct sun. It is necessary, however, to watch 

 carefully, to guard against desiccation and consequent 

 death of the larvae. 



Larvae kept in flat, partially glazed earthenware 

 vessels, with a certain amount of mud, and placed in the 

 sun, develop more quickly than those kept in bottles. 



It is of course necessary to make certain that 

 foreign ova or young larvae are not introduced with 

 the fresh water. 



Some larvae are exceedingly difficult to rear 

 artificially, notably those of M. barbirostris and 

 M. nigerrimus. They remain for long periods with- 

 out perceptibly increasing in size, and frequently die. 



(B) An alternative and less tedious way is to 

 examine nearly-adult larvae found in nature, and to 

 observe, after accurately noting the larval characters, 

 what genera and species of Anophelines eventually 

 hatches out. 



By examining the larva on a slide with or without 

 a coverglass, the main characters may be noted without 

 in any way damaging the larva, which later becomes 

 a nymph and eventually an imago. 



The characteristics of the larvae which are of 

 specific importance are, as we have seen 



1. The antennae. 



2. The clypeal hairs. 



3. The leaflets of the palmate hairs. 



4. The segments carrying palmate hairs. 



