28 STUDIES IN INSECT LIFE, ETC. 



them to float, and the larvae, unlike those of 

 Anopheles, but like those of Culex, hang down into 

 the water by single respiratory tubes. 



They seem to bite all the twenty-four hours 

 round, and although we have not been able to 

 isolate the organisms which cause yellow-fever, 

 there is no doubt the fever is conveyed by this 

 species of mosquito. 



There are also a number of biting flies, such 

 as the Tsetse fly, which suck blood greedily, 

 and the blood-sucking maggot of a fly, a larva 

 of Auchmeromyia luteola, which chiefly affects 

 natives sleeping on mats in Central and sub- 

 tropical Africa, and there are, of course, many 

 flies which injure horses and cattle, and materi- 

 ally diminish the value of their hides. Leather 

 plays a very conspicuous part in warfare. The 

 deterioration of hides owing to the warble fly 

 very materially affects the leather market, not 

 to mention the fact that when cattle are attacked 

 the meat is also seriously damaged. 



Let us turn now for a few minutes to the insects 

 that affect the food of man. Both the house- 

 fly and the blue-bottle fly act in this manner. 



