100 CAROLINE BURLING THOMPSON 



is greatest, but are present in the lower genus Calotermes, where 

 the castes are few. 



Bugnion states his general conclusion in the following words: 

 "Ma conclusion est que la differentiation s'effectue dans la phase 

 embryonnaire pour les trois castes." 



Knower ('94) reports the origin of the soldier of Eutermes 

 (rippertii?) from a form which resembles a worker. 



The adult soldier of this Eutermes has a frontal horn or proc- 

 ess, a large frontal gland, small jaws, and thirteen antennary 

 segments. The adult worker lacks the frontal horn and frontal 

 gland, but possesses very large jaws and fourteen antennary 

 segments. Among his first collections Knower could distinguish 

 only worker 'larvae.' He then found a 'larva' with thirteen 

 antennary segments, which was worker-like in its head and 

 jaws but possessed a small frontal gland. Later a young soldier 

 was discovered in the act of molting. The cast skin was worker- 

 like, as shown by the head and jaws, but the newly molted soldier 

 had the characteristic small jaws, longer head with the frontal 

 horn, and a large frontal gland. 



This discovery of Knower' s seems to indicate that, although 

 in its early stages the soldier caste of this species of Eutermes 

 can not be distinguished from the worker by external characters, 

 it does possess, probably from the moment of hatching, one in- 

 ternal character, namely the frontal gland, and probably more, 

 which differentiate it from the worker caste. 



Snyder ('15), in a study of the biology of the termites of the 

 eastern United States, has investigated the later stages of de- 

 velopment of the nymphs of Leucotermes flavipes, L. virginicus, 

 and Termospis angusticollis. In regard to the earlier stages of 

 development Snyder merely restates Grassi's view that the 

 recently hatched 'larvae' are all alike and undifferentiated; the 

 following quotations, however, show that he may doubt the 

 accuracy of Grassi's classic theory: 



P. 41, the writer has observed quiescent stages of undifferentiated 

 (?) larvae . . . . • p. 43, the larvae having belonged to all external 

 appearances'^ to the undifferentiated group." 



* Italics of the present writer. 



