64 GENERAL ZOOLOGY 



customs of the people, save only that they did not allow them- 

 selves to be bitten by the Anopheles mosquito, which swarms 

 in that region at the close of day. They slept during the 

 night in a mosquito-proof house, and did not contract malaria. 

 Persons, on the other hand, with no traces of malaria, have 

 allowed themselves to be bitten, and thus contracted the 

 disease. It seems, from these and other experiments, that the 

 malarial parasite is injected into the blood with the saliva of 

 the insect, and it further appears that, in order to complete 

 the life-history of the parasite, it must enter the salivary 

 gland of the mosquito. Quinine is a specific, because it kills 

 the organism at a certain stage in its life-history. United 

 States army surgeons in Cuba have been instrumental in 

 clearing up the life-history of the yellow-fever germ, which 

 seems to be transmitted by mosquitoes of the genus Stegom'yia. 



Many localities can be practically rid of these pests by the 

 drainage of the swamps or ponds in which they breed; by 

 the use of kerosene on the surface of such waters ; or by 

 the introduction of fish that feed on the larvse. Among the 

 fishes recommended are sunfish and sticklebacks. It must 

 be remembered that the insect will breed successfully in any 

 transient pool of water, or in any receptacle where water is 

 left standing long enough for the changes just described to 

 take place. Experiments are being conducted in the Middle 

 West with a fungous disease similar to that which destroys 

 large numbers of flies in the autumn. 



Definition of Diptera (Gr. dipteros, two-winged). The in- 

 sects collectively called flies agree in the possession of two 

 wings, the place of the posterior pair being taken by the bal- 

 ancers, which may therefore be considered reduced wings. 

 The flies belong to the order Dip'tera. The Diptera have the 

 mouth-parts fitted for sucking or piercing. They undergo a 

 " complete " metamorphosis. The larvse are commonly known 

 as maggots. 



