LIFE HISTORY AND SEASONAL PREVALENCE 1 



Lynch Arribalzaga (L. A., p. 28) classified Mosquitoes, 

 as regards their habits, into domestic, field, marsh and 

 wood Mosquitoes; and Ficalbi (F. V. S., p. 62) into 

 " foveal," which I take it, may be translated as domestic, 

 paludal, and subpaludal species. 



The word paludal, however, appears to be a misnomer 

 based on an unconscious remembrance of bygone notions of 

 the etiology of malaria, for all marshes of dimensions 

 worthy of the name, shelter too many of the greatest 

 enemies of the larvae to be regarded as the typical habitat 

 of any species ; and for practical purposes, it is more 

 convenient to divide them into domestic and field Mos- 

 quitoes ; though the true forest gnats, such as the genera 

 Megarhina, Sabethes, Mdes, JEdoinyia, and Ceranotcenia 

 mostly, which inhabit the depths of tropical jungles, far 

 from the haunts of man, form a class by themselves. 

 Psorophora and Mucidus are field rather than jungle gnats, 

 and Stegomyia and Armigeres, are rather field than 

 domestic, and are never, so far as I know, found in dirty 

 water. I know of no really jungle species of Anopheles, 

 all species being either field or domestic, but Culices are 

 found in all possible situations. 



It would be a mistake to attempt to attach too rigid a 

 signification to terms of this sort, and I would particularly 

 caution against premature attempts at generalisation, but 

 broadly speaking, the domestic gnats are those which infest 

 habitations, while their larva? are mostly found in small 

 artificial collections of water, such as garden tanks, broken 

 crockery filled by rain, waste water puddles and so on ; 

 while the field species, though often found in and about 

 habitations, pass their larval stage in fairly clean, natural 

 pools, or at any rate in such as afford conditions similar to 

 those found in the open. 



Some typically domestic gnats, such as C. fatigans, will 

 deposit their eggs in the foulest of water, and I have found 

 its larvae in apparently flourishing condition, in the small 

 cemented tanks, for the temporary storage of sullage water 

 in Indian towns, known as nahhdan, the contents of which 

 are filth, far more concentrated than the sewage of any 



