BRAIN OF THE 'WHITE AXT' 555 



the sections of this caste frequently imperfect. \Miole mounts 

 of the true adult and other brains were also made. It should 

 be stated here that on account of the internal chitin of the 

 tentorium, in addition to the chitin in the cuticula of the skin, 

 the termite head is a difficult object to section. Cnly the pro- 

 longed time in paraffin has given good results. The sections 

 were stained on the slide with (1) Ehrlich's acid haematoxylin 

 and eosin, or (2) iron haematoxylin and orange G. 



For the adult sexual forms, I am indebted to Mr. A. D. Hop- 

 kins and Mr. T. E. Snyder of the division of forest entomology 

 of the U. S. Department of Agriculture, who have kindly fur- 

 nished me with young and old adults of both the 'ti-ue' and the 

 neoteinic type with short wing pads, and with much other 

 termite material that will be utilized later. I wish here to exjiress 

 my thanks to both ]\Ir. Hoi)kins and Mr. Snyder for thcii- kind- 

 ness in sending me this material. 



'iiii'] Mi;.MUi;i{s oi' iiii: colons oi- i.. flampks 

 /. The ndult easier and the young 



The colony of Leucotermes flavipes is composed of many 

 difTerent kinds of individuals, some of which are adult or final 

 stages, the castes, while others are merely the young, or the 

 developmental stages of the castes, their presence, in some 

 degree, depending upon the season of the year Each caste 

 contains both males and females, caste not corresponding with 

 sex, as in the bees and ants. 



The term adult is here used in the general and biological 

 sense to denote an insect which has undergone its last molt, 

 and which has, in general, acquired its final definitive form 

 and structure. The phrase "in general" is inserted to co\'er the 

 cr.se of those older females whose abdomens have become great- 

 ly enlarged in the course of egg-laying. I am aware that some 

 biologists would exclude from the category of adult stages the 

 neoteinic reproductive forms and the sterile workers and soldiers, 

 on the ground that the former do not possess the outer bodily 

 structure characteristic of the species, as seen in the 'true' adult, 



