ORIGIN OF CASTES OF TERMITES 101 



Snyder records numerous observations on the quiescent stage 

 of termites preceding a molt, which was first observed in L. 

 flavipes by Wheeler, and described by Strickland ('11). He 

 also describes and figures ('15, PL IX), the molting of soldier 

 nymphs from worker-like forms with mandibles of the worker 

 type. This phenomenon was observed in the three termites: 

 L. flavipes, L. virginicus, and Termopsis angusticollis. 



Mr. Snyder has kindly allowed the present writer to examine 

 the mounted heads of soldiers of L. flavipes and L. virginicus 

 which had just molted from a worker-like skin, on which the 

 workerlike mandibles are clearly seen. It is interesting to note 

 that in both species the newly molted soldiers have a large well 

 defined frontal gland, which, in the worker, is merely vestigial 

 (Thompson ('16) pp. 582-583) . This fact proves for Leucotermes, 

 as Knower's work did for Eutermes (rippertii?), that the worker- 

 like nymph from which the soldier develops resembles the worker 

 in external characters only, but internally possesses the dis- 

 tinctive organs of the soldier caste. 



THE ORIGIN OF THE CASTES OF L. FLAVIPES AND L. VIRGINICUS 

 A. INTRODUCTORY REMARKS 



The present writer approached the problem of the origin of 

 termite castes with the belief that the food hypothesis, founded 

 as it is upon unproved assumptions, is inadequate to explain 

 the phenomenon of differentiation, and with the hope that care- 

 ful staining methods might reveal structural differences in the 

 'undifferentiated' or newly hatched nymphs. 



My lack of belief in the food hypothesis is based upon the 

 following reasons: 



1. It has been stated that certain groups of the young nymphs 

 are selected by the colony for special care, but, in opening a 

 nest of L. flavipes, the youngest forms are found in masses, 

 packed close together and filling a small cavity. There does not 

 seem space enough for any effective selection within a group, and 

 it is not known that the younger stages of the different castes 

 are kept apart or in separate places in the nest; indeed, in col- 



