780 PATHOGENIC PROTOZOA 



quiet water, it is evident that the least wave action is fatal to the 

 mosquito. 



The nature of the breeding place is characteristic, to a certain 

 extent, of each genus of culicidce; stegomyia (cedes calopus), the car- 

 rier of yellow fever, for example, is strictly domestic and breeds in 

 water jars, tin cans, old beer bottles and other artificial collections 

 of water ; wyeomyia breeds exclusively in the fluid at the base of the 

 leaves of air plants; (bromeliads) the anophelines, while domestic to 

 the extent that they live near human habitations, require natural col- 

 lections of water for breeding places, such as sheltered spots along the 

 overgrown banks of streams, temporary puddles and even in water in 

 the footprints of man and animals. 



A proper classification of mosquitoes requires considerable train- 

 ing, but the following points will suffice to separate the anophelines 

 from other mosquitoes. On either side of the proboscis, as seen under 

 a hand lens, are two pairs of organs; next to the proboscis are the 

 palpi, and outside of these the antennae ; the latter serve to distinguish 

 the sexes, the antennae of the male being heavily ornamented with a 

 bushy, hairy investment (plumose) ; the female antennae, on the con- 

 trary, are provided with relatively few, short hairs, arranged in rings 

 at the joints (pilose). In the anophelines the palpi in both sexes are 

 long, at least as long as the proboscis, while in all other mosquitoes 

 they are short in the female or in both sexes. This is the principal 

 differential point. The wing markings are of some help, since ano- 

 pheline wings are almost always spotted. Quite characteristic also is 

 the position assumed by both genera while at rest; among the ano- 

 phelines the head, thorax and abdomen are all in a straight line and 

 the insect makes an angle with the surface upon which it rests ; while 

 the culicidse are hump-backed, the thorax and head are bent on the 

 abdomen so that the latter lies parallel to the surface. By these char- 

 acteristics it is easy to identify a mosquito as an anopheline, but the 

 further classification into species is less simple, and works on ento- 

 mology must be consulted. 



The life history of the anophelines is not yet completely known ; 

 they fly and bite at dusk and dawn and during the night, and thus 

 differ from stegomyia and most other culicidae, which are day-time 

 biters. Their breeding places have already been described ; of special 

 importance are the temporary collections of water in which the larvae, 

 unhampered by their natural enemies, quickly reach maturity in large 

 numbers. With abundance of food and warm weather, the larvae may 



