THE ISOPTERA 93 



protection of the colony, but numerous observations which show the 

 workers to be better fighters, throw doubt upon the real duties of this 

 caste. 



Other castes besides those already mentioned have been discovered 

 in different species of Termites, at least 15 having been recognized, though 

 not for any one species. In addition to the royal pair, workers and 

 soldiers, however, a caste consisting of individuals generally called 

 complementary kings and queens or neoteinic members of the colony 

 is generally present, at least in the older colonies. This caste is capable 

 of reproduction, though less abundantly so than the true queen, and 

 appears to be produced to continue the colony after her death. 



The most generally common species of Termite in the United States 

 (Reticulitermes fiavipes Kol.) except perhaps in the far South and on the 

 Pacific Coast, does not appear to form large colonies (see Fig. 74). Its 

 nests occur under logs and in them, in fence posts, timbers of buildings 

 or other structures, or in tunnels in the ground, though here usually in 

 near proximity to wood. Centering here they go out through tunnels, 

 always protected from the light, mining in woodwork, honeycombing 

 it and leaving only a thin film on the surface to conceal them and shut 

 out the light. If necessary to reach the wood they desire, they may 

 construct small covered passages over the surface of stone, brick or 

 similar materials, through which they pass. They will also attack 

 books and papers, pasteboard, leather, etc., if stored in dark and moist 

 places. In some cases they attack trees, infesting roots and the heart- 

 wood near the base. Citrus trees in the South are often seriously in- 

 jured by them. Field crops are also affected, the roots being fed upon, 

 and plants in gardens and greenhouses are often attacked, the termites 

 sometimes coming up to the benches through covered tubes, in the latter 

 location, and working first in the wooden bench sides, and then passing 

 to the plants themselves. True queens have seldom been found in the 

 nests of this species. 



Control. — To check the ravages of these insects in buildings, bridges 

 and other structures, all infested wood should be removed. Founda- 

 tions should be of stone, brick or concrete, and as far as possible all 

 timbers should be exposed to light and not be so placed as to become moist. 

 As these insects must have moisture where they are, dryness is an effective 

 protection. Where posts must be set in the ground they should be dipped 

 in coal-tar creosote before setting. In general, ventilation and dryness 

 should be secured whenever possible, as the best protection against the 

 ravages of these insects. 



The Termites are not a large group, probably numbering less than two 

 thousand species, but the size of their nests in the tropics attracts atten- 

 tion, and their habits and colonial life are of much interest. They appear 

 to be most closely related to the Orthoptera. Fossil species are quite 

 numerous. 



