46 



Mosul' rroi'JS 



irritation of the wound is slig-lit in cold weather and only 

 becomes intense durin*:^ g-reat summer heat." 



The purpose of the mosquito poison has been a sub- 

 ject of some conjecture. The old Reaumur hypothesis, 

 that it causes the blood to become more liquid and more 

 readily sucked up by the mosquito, has had its adherents. 



Fio. 3. — 8iiliviiry glands of Culex at right, Anopheles at left : greatly 

 enlarged. (After Christophers.) 



Osten Sackcn and Miall, however, believe that it is prob- 

 able that the piercing mouth-parts of the mosquito were 

 originally acquired for the purpose of sucking- the juices 

 of plants, and Macloskie advances the itiea that the chief 

 food of mosquitoes is not animal blood but the proteidst)f 

 plants, and that probably the poison ejected may i)revent 



