io8 The Termites, or White Ants 



furrow by furrow and clod by clod, but pellet by pellet and grain by 

 grain." 



With a few references to certain special conditions and problems in the 

 termite economy, we must finish our consideration of these highly inter- 

 esting insects. Do the termite individuals of a community communicate 

 with each other, or is the whole life of the colony so inexorably ruled by 

 instinct that each individual works out its part without personal reference 

 to any other individual, although with actual reference to all the others, 

 that is, to the community as a whole? It is pretty certain that termites have 

 a means of communication by sounds. The e.xistence of a tympanal audi- 

 tory organ in the tibiae of the front leg, like that of the crickets and katy- 

 dids, has been shown by Fritz Miiller, and the individuals have a peculiar 

 jerking motion which seems likely to be connected with the making of 

 sounds by stridulation, sounds, however, that are not audible to us. 



The spread of termites from one continent to another, as in the case of 

 Tennes fiavipes from America to Europe, and Termes Iiicijugus from 

 Europe to America, can be easily e.xplained by involuntary migration in 

 ships. In unpacking several cases of chemicals received from Ger- 

 many at Stanford University, scores of termites were exposed when the 

 wooden boxes were broken up. The insects, mining in the wood of the 

 boxes, had protection, food, and free transportation on their long ocean 

 journey from Hamburg around Cape Horn to California! 



In termite nests are often found individuals of other insect orders. So 

 often are such cases noted, and so many are the kinds of strangers likely 

 to be present, that entomologists recognize a special sort of insect economy 

 which they term termitophily, or love of termites! The strangers seem to 

 be tolerated by the termites, and apparently live as gue.sts or conmensals. 

 More than loo species of insects have been recorded as termitophiles. This 

 curious guest-life exists on even a much larger scale in the nests of true 

 ants, in which connection it is called m)Tmecophily (see p. 552). 



The most important problem, and one whose solution will require much 

 exact observation (and, if possible, experimentation), is that of the origin, 

 or causes of production, of the different castes or kinds of individuals in 

 the termite community. It has been determined by various observers that 

 all the termites of a community are apparently alike at birth. That is, 

 there is no apparent distinction of caste, no separation into workers, soldiers, 

 and perfect insects. The soldiers and workers are not, as was formerly 

 thought, the result of the arrested development of the reproductive organs. 

 They are not restricted to one of the sexes. If then it is not arrested develop- 

 ment, or sex, or embryonic (hereditary) differentiation, what is the cau.sal 

 factor? Grassi, an Italian student of the termites, thinks that it is food; 

 that the feeding of the young with food variable in character brings about 



