302 A BOOK OF INSECTS 



be the effect of cohabitation rather than its determining 

 cause, for adult termites habitually pass on food to their 

 kindred, old and young alike, while there is a constant 

 interchange of courtesies within the nest. We must 

 assume, therefore, that a desire for companionship, coupled 

 with an instinctive appreciation of the advantages which 

 arise from combined action in the fields of labour and of 

 war, are the factors which have called termite communi- 

 ties into being. In other words, they probably represent 

 an extreme elaboration of the gregarious habit which 

 obtains among locusts and caterpillars. 



Termites inhabit the warmer regions of the globe, and 

 attain their zenith of power and prosperity in the tropics, 

 only two European species being known. The population 

 of a termitarium (i.e. a community or state of termites) 

 varies from a few hundred in some species to millions — 

 it may be hundreds of millions — in others. The castes 

 are always strongly marked, and a given nest may com- 

 prise a bewildering variety of forms. But there are always 

 two sharply distinguished general classes, to wit, the pro- 

 pagators and the workers. The latter frequently include 

 a number of individuals (easily distinguished by the great 

 size of their heads and jaws) which are termed " soldiers." 

 These are popularly supposed to defend the nest, yet the 

 gravest suspicions have been cast upon their ability to 

 perform this office, for they are not really such effective 

 combatants as the workers. With their unwieldy jaws 

 they are unable to gnaw wood, or to eat the usual kinds 

 of termite food. Thus, they are condemned (at least 

 in the case of one species) to long periods of starvation, 

 broken at intervals by cannibal orgies. Not only do they 

 devour their dead companions and kill off the sick and 

 maimed, but in times of excitement they are seized with 

 a kind of mania, and destroy five or six of their fellows 



