184 SCHOOL ENTOMOLOGY 



fifteen years ago it was demonstrated that nearly related 

 species of the genus Anopheles are responsible for the trans- 

 mission of malarial fever and that the dreaded yellow fever 

 is spread by the yellow-fever mosquito.* Indeed, these 

 diseases are spread entirely by mosquitoes. As a result 

 of this knowledge Havana and Panama have been prac- 

 tically freed from yellow fever, and large areas of country, 

 formerly almost uninhabitable on account of malaria, have 

 been reclaimed. The yellow-fever mosquito is strictly a 

 southern species, but different species of the malarial mos- 

 quitoes are found in all sections of the country. The latter 

 (Anopheles) may be distinguished from .the common mos- 

 quitoes by the fact that their wings are marked with black- 

 ish spots, the palpi of the females are as long as the pro- 

 boscis or beak, and when they rest on a wall or ceiling the 

 body is held at an angle from the surface, while those of the 

 common species are parallel to it. 



Mosquitoes usually hibernate as adults in houses, barns, 

 or whatever retreats they can find. With the first warm 

 days of spring the females lay their eggs on the nearest per- 

 manent pools and then die. The larvae of different species 

 have quite different food habits and hence are found in 

 different places, but practically all live in stagnant water, 

 and do not develop in damp grass or vegetation as commonly 

 supposed. 'The common house mosquito breeds in rain 

 barrels, open tanks or cisterns, in puddles, ditches, tin cans, 

 ponds, etc. Occasionally a clogged eaves trough will harbor 

 enough water to allow a generation to mature in the water 

 collected. The eggs are laid on the surface of the water and 

 hatch in a day or two. The larvae are the well-known 

 " wrigglers," and feed on small animals and vegetable life 

 in the water. Those of the house mosquito may be seen 

 * JEdes calopus Meig. 



