206 MOSQUITOES OF NORTH AMERICA 



Mr. Jennings states that this species is very rare or can not be found at all, but 

 Anopheles eiseni takes its place as a wild, undomesticated species. 



James and Liston have a significant statement which bears upon this differ- 

 entiation in regard to domesticity among the different species of Anopheles in 

 India. 



" It is a well recognised fact that some species of ' anopheles ' are more com- 

 monly found near villages and dwellings than others. We may, in fact, divide 

 these insects broadly into two classes : the ' domestic ' species, which are usually 

 found near human dwellings, and the ' wild' species, wliich are rarely found in 

 houses. Of the first class, A. rossi is a typical example, and of the second A. 

 harbirostris. Some species would appear, as regards this habit, to occupy a place 

 intermediate between the typically domestic and the typically wild species. 

 A. fuliginosus, for example, may, in certain parts of India, be found in enormous 

 numbers in the sheds and outhouses on the outskirts of a village, while in other 

 parts, though large numbers may be caught in tents pitched at some distance 

 from a village, few or none will be found in the houses of the village itself. 



" It is usual to say that the greater the number of ' anopheles ' there are in a 

 place, the greater will be the prevalence of malaria. This is not by any means 

 borne out by experience. We have already mentioned that some species of 

 ' anopheles ' are better malaria-carriers than others, and apart altogether from 

 the fact that ' anopheles ' may be abundant in a place without there being any 

 malaria there at all, it often happens that the species which is present most 

 abundantly is not the one which is carrying malaria at the time. It is, however, 

 a difficult matter to estimate the relative abundance of different species in any 

 place, for some are much more easily seen than others, and the habits which some 

 species have of secreting themselves among the straw of a thatched roof and of 

 resting only upon objects which are as nearly as possible the same colour as they 

 are themselves, are very important. In order to exemplify this, it seems worth 

 while to recount an instance which happened in our experience. In the malari- 

 ous village of Ennur in the Madras Presidency, A. rossi was so abundant that on 

 almost every straw of the thatched roof of every house three or four specimens of 

 this species were resting. A careful search in the ordinary way did not reveal the 

 presence of any other species, and it is certain that, had there been no other 

 object in the search than the mere determination of the species of * anopheles ' 

 present in the village, the observer would have gone away quite satisfied that 

 A. rossi was alone present. But the village was an extremely malarious one, and 

 knowing that A. rossi was an inefficient carrier of malaria in nature, he was 

 unwilling to believe that no other species was present in the houses. Fixing his 

 mind, therefore, upon the thought that he was looking for A. culicifacies and not 

 for A. rossi, he again commenced the search with great care, and was rewarded 

 not only by detecting the presence of A. culicifacies, but by catching a sufficient 

 number of this species during several days' work, to prove that it was the species 

 responsible for the prevalence of malaria in the place and not the very much 

 more abundant species /I. rossi/' 



HIBERNATION AND /ESTIVATION. 



Anopheles pass the winter, for the most part, in the adult condition. In 

 regions with a rigorous climate the fecundated female is the only form that sur- 

 vives the winter and starts a fresh generation with the return of mild weather. 

 Smith has shown that in New Jersey they begin to seek winter quarters in Sep- 

 tember. He dissected specimens during the winter and found the alimentary 

 canal empty and the ovaries undeveloped. In the early winter he found the 



