108 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 existence 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 Muller, 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 
Termes flavipes from America to Europe, and Termes lucijugus from 
Europe to America, can be easily explained 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 guests or conmensals. 
More than ioo 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 myrmecophily (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 causal 
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 
