436 MOSQUITOES 



widely distributed yellow fever mosquito, Aedes calopus (or 

 Stegomyia fasciata) (Fig. 201), feeds by preference in the early 

 morning or late afternoon. Here again a knowledge of the 

 habits of particular species is of importance, since it may aid in 

 the intelUgent avoidance of particular disease-carrying forms. 



Food Habits. — Heretical as it may sound, mosquitoes feed 

 mainly on plant juices, honey, etc. It is doubtful if the males 

 of any species normally suck blood, and even the females of some 

 species are strict vegetarians. On the other hand, the females 

 of many species have a voracious craving for warm blood. Some 

 species indiscriminately attack any warm-blooded or even cold- 

 blooded animal, while others show strong preferences. The 

 yeUow fever mosquito normally feeds chiefly on man, and even 

 discriminates against the black race. The other " domestic " 

 mosquitoes apparently have a strong liking for human blood also, 

 and it is not unlikely that their domestic habits are the result 

 of their taste for human blood. Knab found that Aedes spenceri 

 of the Saskatchewan prairies would fly toward any large object. 

 On the prairies such an object would usually be a large animal 

 and the mosquitoes would fly toward it instinctively in the 

 hope of satiating the craving for food. 



Hibernation. — The method employed by mosquitoes for 

 passing the winter in cold climates, and the dry season in the 

 tropics, varies with the species. Many of the mosquitoes of 

 temperate climates and many in the tropics hibernate or pass the 

 dry season in the adult stage, the females stowing themselves 

 away in hollows in trees, caves, crevices in rocks, cellars, barns, 

 etc., to come forth and lay their eggs in the spring. A few species 

 hibernate in the larval stage, the larvse of one species, Wyeo- 

 myia smithii, becoming enclosed in solid ice in the leaves of the 

 pitcher plant in which they live. Most hibernating larvae retire 

 to the bottom of their breeding pools during cold weather and 

 do not survive freezing. The majority of temperate- and warm- 

 climate mosquitoes and all of the northern ones pass the un- 

 favorable season in the egg state, and this may be looked upon as 

 the common method of hibernation. 



Length of Life. — ■ The length of life of mosquitoes varies with 

 the species and with the sex. Male mosquitoes seldom live more 

 than from one to three weeks; their duty in life is done when they 

 have fertilized the females. The latter usually die shortly after 



