208 MISC. PUBLICATION 273, U.S. DEPT. OF AGRICULTURE 



timbers and telephone poles; but usually their work is of no 

 economic importance. Their work differs from that of the 

 carpenter ants in that the burrows are partitioned into larval 

 cells by chips of wood cemented together to form circular or 

 spiral discs. Many species of these bees are found throughout 

 the Western States, but they are particularly numerous in the 

 Southwest. 



TERMITES 



The termites (5, 97, 11,2, 1U, U6, U7, 156) (Isoptera) are a 

 very destructive group of wood-boring insects that excavate large 

 cavities in wood, and at times so mine the interior as to leave 

 only a paper-thin shell. In the forest they are commonly found 

 in the wood of felled trees, in snags killed by bark beetles or 

 fire, and in stumps or other sections of dead or decaying wood. 

 Insofar as they reduce forest debris they are beneficial, but they 

 are exceedingly destructive when they turn their attention to 

 fences, telephone poles, buildings, furniture, or other utilized 

 cellulose products. The group as a whole finds its greatest 

 development in the Tropics, and in the United States does the 

 most serious damage in the warmer southern latitudes. A large 

 number of species are found in the Southwest and southern 

 California, but only a few extend their range into the Pacific 

 Northwest and northern Rocky Mountain region. 



Termites are dirty-white, soft-bodied insects that live in 

 colonies in the wood or in the ground and expose themselves to 

 the light only when in the mature winged adult form. Each 

 colony is made up of several specialized forms, such as workers, 

 soldiers, king, and queen or else secondary sexual forms (fig. 100). 

 They look like soft, fleshy ants, but are distinguished from ants 

 in having weakly sclerotized body parts, except the head; and 

 the winged forms have four wings of quite similar size and shape, 

 while the true ants have hind wings smaller than the forewings. 



The social life of these insects is very interesting and compli- 

 cated. Their excavations in wood are hollow, completely enclosed, 

 more or less longitudinal cavities, in which some species deposit 

 small, impressed pellets of excrement (65). The destructive sub- 

 terranean form deposits liquid feces which make only charac- 

 teristic spottings in their galleries. 



The control of termites consists in isolating wood material 

 from contact with the ground, or impregnating it with creosote 

 or other termite-repellent materials. Very detailed methods of 

 control have been devised, and it is recommended that the reader 

 consult one of the publications devoted to the control of these 

 insects (97, 11$, 1U, 156). 



INSECTS INJURIOUS TO FOREST RANGE PLANTS 



Grasses, herbage, and browse, which furnish feed to range ani- 

 mals, comprise a forest product sometimes of greater economic 

 importance or value than the trees that grow on the area. These 

 grazing plants may also suffer from insect attack and at times 

 are so completely destroyed in certain localities that cattle and 



