64 MOSQUITOES 



eludes other blood-suckiiii^' insects from being' possil)le 

 hosts of nuilarial parasites on the strength of his sup- 

 posed geographical agreement. 



G. Since the geogra})hical distril)ution of Anoplieles in 

 England is wider than the fornu'r distril)ution of ague in 

 that country, Ave are forced to conclude that it is not a 

 matter of the geographical distriljution of Anopheles as 

 much as of their numerical distribution. 



7. Our observations having proved the existence of 

 Anopheles in non-malarious districts, we believe that they 

 will explain the occasional occurrence of ague in out of 

 the Avay places, without making it necessary to assume 

 that nndaria-bearing mosquitoes have been freshly im- 

 ported, for, given suitable conditions of temperature and 

 the requisite number of Anopheles, a malarious subject 

 coming from other parts might well infect the local in- 

 sects, which in turn would spread the infection to healthy 

 persons. 



8 We Avould suggest to those engaged in the investi- 

 gation of malaria in other countries, that they search as 

 carefully for Anopheles in non-malarious as in malarious 

 regions. More data as to the number of these insects in 

 various localities are certainly required, though we are 

 fully aware that numerical estimates permit of a consider- 

 able degree of error. Nevertheless, they would always 

 possess a relative value. 



Grassi has repeatedly asserted that the geograi)hic dis- 

 tribution of Anopheles in Italy coincides with that of 

 inalaria, and on the strength of their wider geographic 

 distribution he excludes a number of blood-sucking creat- 



