62 HAROLD HEATH. 



Sonic species are said to cement the particles together by means 

 of saliva or material regurgitated from the anterior part of the 

 alimentary canal, while others employ the method of Tcnnopsis 

 and Calotermes. These, carrying a pellet in their mandibles, 

 travel to some spot where building is required, and, feeling about 

 with their antennae, locate a breach in the wall. Facing about 

 they then deposit a drop of liquid proctodeal material into which 

 the excrement is quickly pressed with many waggings of the 

 head, and immediately rush after another pellet which is like- 

 wise stuck fast. By this time the cement has set and the worker 

 or nymph departs into the crowd, where it rests and is groomed 

 by its fellows. In their natural surroundings the amount of 

 building done by these insects is relatively small, but colonies 

 kept in glass cases and in the presence of sufficient moisture, 

 erect low but extensive roofs, elevated on many pillars, that serve 

 to protect them from the light and other injurious agents. 



It is now thoroughly well established that the soldier and 

 worker in the termite colony are not the result of the arrested 

 development of the reproductive organs. It has also been shown 

 that they are not restricted to either sex. And it is almost 

 equally certain that their differentiation is not to be traced back 

 to the newly hatched young. The latter, when they first appear, 

 are exactly alike in form and color, though they may exhibit 

 slight differences in size, and the characteristics of the different 

 castes develop at varying times after the first molt. If then 

 neither arrested development, nor sex nor heredity are directly 

 responsible for the production of soldiers and workers, what is the 

 agent immediately concerned? Grassi is of the opinion that it is 

 the food. Owing to its character or amount or both, the royal 

 pair or the colony are able to transform the larvae into soldiers, 

 workers or perfect insects. Such a belief gains some support 

 from allied phenomena among the social hymenoptera, but at the 

 present time very little definite knowledge exists regarding this 

 subject for the termites. For months I have fed a large number 

 of termite colonies of all ages, with or without royal pairs, on 

 various kinds and amounts of food --proctodeal food dissected 

 from workers or in other cases from royal forms, stomodeal food 

 from the same sources, sawdust to which different nutritious in- 



