Changes in the Life-cycle 319 



other individuals, their own saliva and that of others, and water. 

 The faeces form an important element in the diet. "When a 

 calotermite wishes to feed, he accosts one of his fellows and ca- 

 resses the abdomen with the antennas and palpi. If the one thus 

 accosted is prepared to eliminate, he at once extrudes the scyba- 

 lum from the anal aperture. The other then removes it, chiefly 

 by aid of the auxiliary palpi, and usually in two operations 

 separated by a short interval, drawing it at first half, and then 

 completely out. He then rapidly seizes it with the mandibles, 

 suspending his caresses for this purpose, and when he has 

 possessed himself of it nibbles at and ingests it little by little." * 

 Pellets can sometimes be seen in the mouth composed of re- 

 gurgitated food, which is at times used for building, but may be 

 seized and eaten by another individual. The saliva may be 

 used either as cement in building or as food for others. It is 

 given in abundance to larvae that are too young to eat wood, and 

 to those that are in course of becoming royal substitutes. These 

 individuals, fed with saliva, "exhibit a great transparency of the 

 abdomen, an indication that they are in process of becoming 

 royal substitutes." Their digestive tract contains no proto- 

 zoans that are usually present in other forms. Possibly they 

 have been killed by the saliva. These and other facts suggest 

 that the saliva is the cause of the transformation of young ter- 

 mites into substitute forms. What determines whether a young 

 termite is to become a soldier or a worker is not known; but 

 Grassi thinks that this difference is also determined by the food. 

 These experiments and observations leave little doubt that 

 the different castes of termites arise from the same kind of egg, 

 and are not predetermined in the egg. Each egg has the possi- 

 bility of becoming a royal form, a royal substitute, a worker, or a 

 soldier. It is probable that the results depend on the amount 

 or the kind of nutrition that is given to the young by the older 

 members of the community. 



* In the honey bee the relation between the food and the develop- 

 ment of the worker and queen is better understood. It appears 



1 Translated by W. F. Blandford. 



