245 



1. Remove the paper upon which the ova 

 have been laid (p. 96), and place in a small 

 bottle containing some filtered fresh water from a 

 pool or rain puddle. 



2. Place in a good light, but take care that 

 the sun, by the focussing action of the glass, does 

 not heat the water, otherwise the larvae will be 

 killed. 



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 

 earthenware 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 earthen- 

 ware 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. sinensis. 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 species of Anopheles eventually 

 hatches out. 



