THEIR RELATION TO MAN 



191 



after all, for in the larval stage they are nearly all mag- 

 gots, similar to those of the common house fly. Wher- 

 ever an animal dies, a mass of excrement drops in the 

 field, an over-ripe fruit falls to the ground or a pail of 

 garbage is set outdoors, there we find flies present at 

 once and in a few hours young maggots. It has been 

 said that flies will devour an ox more rapidly than a lion 

 and while that may be a little exaggerated, they will 

 certainly make a more complete job of it. It is literally 



Fig. 87.' 



-Pommace fly; Drosophila ampelophila: a, adult; b, larva; 

 d, e, pupa. 



astounding to note how rapidly a small carcass may be 

 transformed into a mass of squirming maggots, ap- 

 parently liquefying the tissues so that they may be ab- 

 sorbed through the small mouth orifice. And it needs 

 so little to attract these flies. Lay out a few bruised 

 apples, pears or other fruit on a table, and in a short 

 time they will be covered with little yellowish or gray 

 flies having bright, brick-red eyes — pommace flies — 

 coming from no one knows where, but attracted by the 

 odor of the ferment. In the fall when cider or wine is 

 making, every tub or barrel of must is an attraction, 

 and in the ferment thrown out of the bung of the wine 

 cask the larvae occur by the hundred. Not long as 



