CLASSIFICATION AND DISTRIBUTION 



111 



The termites are especially abundant in the tropics. 

 Some species build large mounds, twelve feet or more in 

 height. Their food is chiefly wood, and they often destroy 

 buildings and furniture. Jamestown, the capital of St. 

 Helena, was largely destroyed by termites and had to be 

 rebuilt on that account. Though less numerous in the north- 

 ern United States, 

 houses are some- 

 times greatly dam- 

 aged by them. 



Degrees of Spe- 

 cialization. The lack 

 of special adapta- 

 tions or modifica- 

 tions of the various 

 organs marks the 

 ancestral insects as 

 generalized forms, as 

 distinguished from 

 their more or less 

 specialized descend- 

 ants of today, in 

 which the organs 

 have become modi- 

 fied to perform different functions. Thus the greatly de- 

 veloped hind legs of the grasshoppers are a specialization 

 in structure, fitting the insect to progress by leaps as well 

 as by walking. 



Very different degrees of specialization often exist in the 

 organs of the same species ; thus the digestive system of the 

 grasshopper is quite complex, while the separate prothorax 

 is a generalized character, which shows the grasshopper to 

 be allied in this respect more closely to the primitive type 

 than are insects like the wasps, for example, where the three 



Fig. 67. Termites or white ants. 

 (Much enlarged) 



A, female ; B, male. (From United States Depart- 

 ment of Agriculture, Bulletin No. 1^72) 



