64 



ANIMALS OF LAND AND SEA 



into them as they slept, and, much more frequently, by larvae 

 hatched from eggs laid in the nose or on sores and ulcers. 

 A few flesh-flies hve in excrement or in rotting plants, and some 

 in other insects and in snails. 



Since, if exposed, a dead bird or rat would soon be consumed 

 by flies, some of the large carrion beetles go to great pains to 



bury the car- 

 cass in the 

 ground out of 

 reach of the 

 flies, thus insur- 

 ing a supply of 

 food for their 

 own young. 



The excre- 

 ment of animals 

 forms the food 

 of many sorts of 

 flies and beetles, 

 and some 

 moths; and 

 some of the 

 beetles, like the scarabs, bury balls of it in the same way that 

 sexton beetles bury carcasses. Its odor, like that of carrion, is 

 highly attractive to many butterflies. Many flowers have one 

 or other of these odors, and thus attract the corresponding 

 insects. 



From this brief sketch, which might be indefinitely length- 

 ened and is perhaps too short, it is clear that insects feed not 

 only upon vegetable material in all forms, but upon each other, 

 upon all other kinds of animal matter both living and dead, 

 and upon all kinds of waste material. In other words, where- 

 ever in nature there exists a constant supply, continuous or 

 intermittent, of any substance whatsoever available as insect 

 food, some insect t}'pe makes use of it. 



Many insects, and even large groups of insects, are extra- 

 ordinarily restricted in their diet, for instance the cockroach 



Fig. 41. A Macrourid. 

 For explanation of the figure see p. xii. 



