434 MOSQUITOES 



United States, Culex territans, does not annoy man does away 

 with the necessity of combating this species, and obviates the 

 necessity of destroying larvae in certain kinds of marshes and 

 pools where this is practically the only breeder. Again, the 

 fact that mosquitoes breeding in crab holes do not annoy man 

 eliminates the necessity of attempting the almost impossible 

 task of destroying such breeding grounds in order to be free of 

 mosquitoes. The fact that a certain species of Anopheles, A. 

 malejactor, which is a tree-hole breeder, is not a malaria carrier, 

 saved thousands of dollars in the anti-malarial fight in the 

 Canal Zone. 



Habitats. — A classification of mosquitoes according to habi- 

 tats and breeding grounds has been attempted by some authors. 

 Dr. J. B. Smith, for instance, divides the mosquitoes of Ncav 

 Jersey into four ecologic groups, the salt marsh, house, swamp, 

 and woodland mosquitoes. However, almost as many different 

 ecologic groups could be made as there are species of mosquitoes 

 or possible breeding and foraging places. There are species 

 which breed in reedy swamps, woodland pools, eddies of rivers, 

 slow-flowing streams, holes in trees, pools of melted snow, salt 

 marshes, tide pools, crab holes, pitcher plants and other water- 

 bearing plants, or in broken bamboo stems filled with water. 

 There are species which have become " domesticated " and occur 

 almost always in the vicinity of houses, laying their eggs in 

 water troughs, street gutters, rain barrels, water-filled cans in 

 garbage heaps, flower vases, water bottles, and anj' other col- 

 lection of water in or about human hal)itations. Some species 

 show almost no preference as regards breeding places, others, 

 especiall}^ those breeding in such specialized places as in water- 

 holding plants, are very closely limited; some species prefer pure 

 clear water, others filthy water, while still others are apparently 

 indifferent. 



Migration. — That mosciuitoes are seldom found far from 

 their Ijrceding grounds is another fact, only recently recognized, 

 of great economic importance. The evidence points to the fact 

 that most kinds of mosquitoes seldom stray more than from half 

 to three-quarters of a mile from their l)irthplace, and usualh^ not 

 over a few hundred yards. The supposition that mosciuitoes 

 utilize a strong wind to carry them long distances is entirely false, 

 since mosquitoes are so delicate as to lie unable to fly at all with a 



