ORIGIN OF CASTES OF TERMITES 99 



Bugnion, who has made extensive studies upon the termites 

 of Ceylon, is the first modern biologist to present evidence for 

 the view that the castes of termites are determined in the egg, 

 before hatching. He states, ('12, '13), that the generally ac- 

 cepted view that the castes are produced by food, the presence 

 of parasites etc. is not in accord with the facts that he has per- 

 sonally observed. 



Among a number of newly hatched nymphs of Eutermes 

 lacustris, examined under the microscope, Bugnion found one 

 individual, 1.3 mm. long, with the distinct frontal horn and well 

 formed frontal gland characteristic of the soldier caste. After 

 further investigation, he states that two or three such nymphs 

 are to be found in every hundred of the newly hatched forms. 

 He concludes from these observations that, in general, the ter- 

 mite soldier type is differentiated in the egg, and that its origin 

 goes back to a deep seated cause, probably analogous to the 

 cause of sex. 



The following facts are brought forward by Bugnion as addi- 

 tional evidence for this view : 



1. In the mushroom- feeding termites no one has observed 

 that tho future sexual forms are given a special food (saliva) at 

 first. 



2. There are no actual observations that the action of saliva 

 affects the egg; the eggs are not sorted into lots, but lie in masses 

 in the niches of the nests, and no one has recorded an observation 

 that some are licked more than others. 



3. The supposed action of the protozoan parasites is not to 

 exert an injurious effect upon the development of the termites; 

 on the contrary, the protozoa are of use, by partly digesting 

 the wood in the intestine before being in their turn digested and 

 absorbed. 



Mon impression, apres avoir examine la question sous tous ses 

 faces, est que les Trichonymphides ne sont pas des parasites, mais 

 que leur existence est liee k celle des Calotermes par une vraie symbiose. 



4. These protozoa are not present in all termites; they are 

 absent from the higher Indian forms, where caste differentiation 



