BENEFICIAL INSECTS 67 



of inks comes from insect-made galls. While formerly many in- 

 sects were used as ingredients in medicaments, now only a few 

 are thus employed. Of these the blister beetles are the most 

 important, especially the Spanish fly, which is collected in vast 

 numbers, dried, and powdered; it has the property of producing 

 blisters when applied to the human skin. 



Food for Man. — Although it is of very little importance, it is 

 interesting to note that certain insects have at various times and 

 in various places been used as food by man. Grasshoppers are 

 eaten by the savages in many countries; when fried, they "are 

 said to have a sweet flavor, while in a stew with milk they re- 

 call oysters." The eggs of a water bug are in some localities 

 in South America gathered, dried, and baked into a cake by the 

 natives, and in tropical countries young ants often serve as food 

 for uncivilized mankind. 



Scavengers. — The benefits derived from insects which act 

 as scavengers are very little appreciated. To determine their 

 effectiveness one has only to place a small dead animal in a field. 

 Flies find the carrion almost immediately, lay their eggs on it, 

 and the maggots which soon hatch from these eggs immediately 

 begin to devour it. The great Swedish naturalist, Linnaeus, 

 once said that a fly could devour the carcass of a horse more 

 quickly than could a lion. The burying beetles also attack 

 dead bodies, digging out the earth from underneath and slowly 

 burying them in the ground. 



Other insects feed upon dead and decaying vegetable matter, 

 reducing such obnoxious substances as the excrement of horses 

 and cattle to harmless material that soon becomes mixed with 

 the soil. In fact " if all the insect scavengers were removed at 

 one time and all dead animal and vegetable material left to other 

 decays, the foulness and noxious odors that would be thus let 

 loose are beyond all description." 



The most interesting of all the scavenger insects are the 

 " tumblebugs " (Fig. 43). The young of these beetles live in 

 animal excrement and the adults are often found in the fields 



