THE HOUSE GNAT 17 



banks of rivers. The species that lay their eggs on 

 the surface of water contained in cesspools, in the 

 dirty water in tubs, bottles in yards, in gutters, 

 choked eaves, rainpipes, broken drains, in exposed 

 collections of sewage, cisterns, flower- vases, or water- 

 pots, are different from those that oviposit in shallow 

 marshes, on the estuaries of rivers, in streams that 

 flow slowly through woods, in the water that collects 

 stagnant at the end of irrigation channels, or in ponds 

 in the jungle. In some places, of course, both kinds 

 of mosquito are found together. For example, in 

 the houses of villages on the borders of swamps, or 

 near ricefields or flooded meadows, and in towns 

 where there is much irrigation, many gardens, or 

 public parks, the species of mosquito found may 

 belong to both the domestic and sylvan families ; 

 but in the larger towns and villages the domestic 

 species are always the commoner even if the others 

 exist. This is because mosquitos will not fly far 

 from their breeding-places unless there happens to 

 be no food for them near : the marsh-gnat will remain 

 near the marsh, the house-gnat will not go far from 

 the backyard. Therefore it may be said that the 

 kind of mosquito found commonly in towns belongs, 

 for the most part, to the subfamily called Culecine ; 

 the Culecina are subdivided again into many 

 genera, the commonest of which are the Culex and 

 Stegomyia ; and these again into many species. 

 It is these which are dealt with here ; other 

 works must be consulted if the malaria-carrying 

 Anopheline is very common in the town. But for 

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