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larvae are extremely difficult to find, wliile in the dryer districts, 

 where adults are relatively scarce, larvae may be found abundantly 

 in the small isolated places where they breed. The explanation given 

 is that on the great expanse of marsh the female Anophehne can 

 choose many favom'able breeding-grounds and disperse her eggs 

 instead of concentrating them at one point, and thus all are favourably 

 placed for development, while in the smaller, isolated breeding-grounds 

 the Anophehne density is hmited by the competition among the 

 larvae concentrated there. It is clear therefore that the number 

 ■of adults observed is the only accurate estimate of Anophehne density. 



Investigations have shown that the Anophehnes have entirely 

 adapted themselves to sheltering exclusively in buildings of human 

 ■construction and inhabited by either man or animals, for unoccupied 

 buildings ofTer no attraction to them. It is evident, moreover, if 

 only from the preponderance of females in buildings containing an 

 animal host, that the shelters are sought for purposes of nourishment 

 and not only for rest. Proof is abundant that A. maculipennis bites 

 most frequently inside buildings, and the type of dwelhng-place 

 described above of!ers most attractive conditions for both nomishment 

 and shelter. From repeated examinations of many of these houses 

 it is clear that the number of Anophehnes attracted to that part of 

 the dwelhng occupied by human beings is quite insignificant compared 

 with the enormous quantities that may be caught in the neighbouring 

 portion of the house occupied by domestic animals. Closer examination 

 reveals the fact that human beings play a most unimportant role 

 in the nutrition of Anophehnes, and that the various domestic animals 

 have not all the same value in this respect, cattle, horses and mules 

 being the favourite hosts, pigs, goats and sheep being less attractive, 

 and the smaller animals, such as rabbits, being of still less importance. 

 Dogs and fowls are rarely bitten. In regions where A. maculipennis 

 is the dominant mosquito it therefore follows that the maintenance of 

 of the former animals in close proximity to human dwelhngs affords 

 almost complete protection to man against the insects' attacks. In 

 the examinations described, the average number of females that had 

 recently drawn blood from man was M"2 per cent., while those that 

 had gorged upon domestic animals frequently exceeded 90 per cent. 

 During the summer season, when the animals are kept out in the open 

 both day and night, the stables no longer ofler any attraction to female 

 Anophehnes, and although many may still be found there, they are 

 invariably fasting and will readily attack any animal host in full 

 dayhght, including man. Wherever the inhabitants of a region 

 complain of mosquito attacks, it is invariably the case that their 

 stables contain but few animals. 



In the Vendee region, two dii?erent sets of conditions occur ; in 

 the drier districts, where the Anophehne density is not very great, 

 the existing mosquitos find sufficient nourishment in the cattle of the 

 district ; man is practically free from attack and may even be 

 unconscious of the presence of large numbers of mosquitos in his near 

 vicinity ; while in the marshy districts, where the Anophehne density 

 is too great to find adequate nourishment in the cattle present, man 

 is undoubtedly attacked, but even then the Anophehnes seem to bite 

 with repugnance and without entirely satisfying their hunger. 



