ANIMALS WITH JOINTED FEET-THE ARTHROPODS 



237 



Fig. 11-31. The dragonfly (Aescha) is noted for its excellent powers of flight and its enormous eyes. It captures 

 mosquitoes and other insects while in full flight. Its two large eyes may possess as many as 30,000 ommatidia, 

 and for that reason are probably excellent photoreceptors. Its antennae are rudimentary and are probably of 

 little importance to the animal. 



causing them distress, as well as making the 

 hide valueless for leather. Finally, there 

 are the millions of gnats, flies, mosquitoes, 

 and bugs that can be rated merely as having 

 a high-grade nuisance value, but do no 

 special harm. 



In addition to transmitting important hu- 

 man diseases, insects attack man's food and 

 either destroy or actually consume it. Cereal 

 grains both in the storage bins and in the 



fields are injured or destroyed by various 

 types of insects. Clothes, furs, and uphol- 

 stered furniture are eaten by the clothes 

 moth. Not only the furniture, but the house 

 itself can be tunneled and destroyed by 

 termites. 



Modifications in form and function 



Although all insects, with few exceptions, 

 have body parts similar to those of the grass- 



