THE PERPETUATION OF THE SPECIES 35 



lay their eggs. For example, in houses, the males of 

 the Culeeines are commonly found in the water- 

 closets. The females are attracted there by the seal- 

 water, for they know that their children will thrive 

 therein ; and also that as soon as they have laid 

 their eggs the males are ready to refertilise them 

 again. The eggs exude their larvae into the seal- 

 water of the closet, the latter are washed down into 

 the cesspool where the water is at an even tempera- 

 ture, and where there is plenty of food for them ; so 

 the perpetuation of the species is assured. As the 

 female lives so much longer than the male, her 

 second and third fecundations are brought about by 

 the males of succeeding generations to her own. This 

 is why males remain near the breeding-places, and 

 their presence in a house is a sure sign that the larvae 

 are near probably in the cesspool of the house. In 

 any tropical town, when a cesspool is opened, 

 thousands of mosquitos fly out. In Egypt these 

 cesspools were the chief breeding-places for the 

 domestic mosquitos. 



A female mosquito having partaken of several 

 meals of blood, and having her ovaries full of matured 

 ova, goes in search of some suitable water collection 

 where she can lay her egg-raft undisturbed, and 

 where she can be certain that her larvae will thrive. 

 She naturally returns to that collection of dirty 

 water where she herself passed her own larval 

 metamorphosis ; for she knows that the water will 

 be suitable for her purpose. After she has laid her 

 eggs, she will find there males of her own species, but 



