man's chief competitors, the insects 63 



Living more or less exclusively on the blood of vertebrates 

 are the bed-bugs, Hce, ticks, and some mites. Others sucking 

 it whenever they get a chance are hosts of other insects, various 

 large and vicious bugs, mosquitoes, horse-flies, stable-flies, 

 tsetse flies, a few midges, black flies, deer flies, sand flies, 

 fleas, jiggers, and red-bugs and other mites, many of which 

 are terrible pests in certain places. 



The true jigger, which is a kind of flea, is an interesting 

 creature — when it is observed in someone other than yourself. 

 The female burrows into the skin and the hinder part of her 

 body then swells into a large ball fuU of eggs. If this be not 

 removed a serious sore wiU foflow. Yet the young jiggers, 

 like all young fleas, live on decaying particles which they find 

 in dust and dirt and are not parasitic. 



Dead animals provide food for quantities of flies and many 

 beetles, by which in the warmer months they are soon con- 

 sumed. The blue-bottle and other flesh and blow flies are 

 common examples. The bee-fly, common on the golden-rod 

 in the late summer, lives often in dead animals if very moist, 

 and habitually on decaying substances of any kind, especially 

 in water, being enabled to breathe by extending the hinder 

 part of its body to the surface in the form of a long tube. The 

 adult bee-flies were mistaken for bees by the ancient Greeks, 

 who observed them emerging in swarms from dead cattle; and 

 this gave rise to the belief that bees were spontaneously gen- 

 erated from dead animals. Another type of bee-fly lives as a 

 scavenger in the nests of bees and wasps. The Esquimaux 

 hold the blue-bottle sacred, since the bodies of their friends 

 and relatives go to make up its substance, and each blue-bottle 

 is supposed therefore to contain a corresponding portion of 

 their souls. Certain carrion flies are sometimes parasitic. If 

 lizards are fed on the larvae of these they will proceed to feed 

 on their internal organs and soon kill them. Or if a lizard 

 eats one of these flies full of eggs these eggs wiU sometimes 

 hatch and the lizard will be eaten out from within. Men 

 have sometimes been killed by carrion fly larvae which bored 



