THE CLASSIFICATION OF INSECTS 



161 



of houses, and in the southeastern states they have been found 

 infesting living plants, particularly orange trees, guava bushes, 

 sugar cane and pampas grass. The largest and most abundant 

 species, Termopsis augusticollis, on the Pacific coast, makes its 

 nest by mining in dead stumps and logs and sometimes ruins 

 telephone and telegraph poles in this way. A single com- 

 munity of this species may include thousands of individuals. 



Order Corrodentia. -The order Corrodentia, or book-lice 

 and bark-lice, is composed of very small insects most of which, 

 composing the family Psocida, have two pairs of wings and a 

 plump rounded body, while the others, 

 forming the family Atropida, have no 

 wings or only small wing scales or buds 

 and a flattened body. The Psocidae 

 are the bark-lice and are commonly 

 found in small clusters on bark, while 

 the Atropidae are the so-called book- 

 lice, common in old books and on dry 

 dead organic matter. 



In both families the mouth-parts are 

 of the biting type, with the jaws especi- 

 ally strong and heavy for the success- 

 ful biting off and chewing of hard dried 

 ( food. Atropos divinatoria is the spe- 

 cies usually found in books. It is 

 about 1/25 of an inch long, grayish- 

 white, with slender projecting antennae, and small eyes look- 

 ing like distinct black spots on the head. It does not limit 

 its feeding to the paste of book bindings but does much dam- 

 age to dried insects in collections. 



Order Mallophaga. The Mallophaga, or biting bird-lice, 

 compose a group of about 1500 known species, all of which 

 live as external parasites on the bodies of birds and mammals. 

 They have strong biting mouth-parts, and feed exclusively on 

 the hairs or feathers of their host. They do not, like the true 

 lice, suck blood. 



The body varies from 1/25 to 1/3 of an inch long, is wholly 

 wingless and much flattened. The insects have no compound 



FIG. 74. A wingless 

 book -louse, Atropos sp. 

 (Much enlarged.) 



