506 



CAROLINE BURLING THOMPSON 



the occasional gland cells are tall and slender, but the majority 

 of the cells are non-glandular. The same non-glandular structure 

 of most of the frontal gland cells may be noted also in the adults 

 of Termopsis, so that, together with the absence of an external 

 opening or fontanel, the frontal gland of Termopsis may be said 

 to be non-functional and merely a primitive form of the elaborate 

 sac-like frontal glands of the higher termites. To draw an 

 embryological comparison, the frontal glands as seen in the first 

 forms of Termopsis and Reticuhtermes, respectively, may be 

 compared in form to the neural-plate and neural-tube stages of 

 an embryo chick. 



Fig. 5 Termopsis angusticollis. First-form adult, frontal section of the 

 head through the frontal gland and anterior part of the brain, fg, frontal gland; 

 hy, hypodermal cells. Spencer oc. 6, obj . 16 mm., stage level, reduced one-third. 



The noteworthy features of the abdomen are in the digestive 

 and reproductive systems and in the fat bod5^ 



In the digestive system, four enteric caeca, or outpocketings 

 between the gizzard and the mid-intestine, may be noted. They 

 are short slender tubes, two dorsal and two ventral, and all of 

 equal size in the reproductive castes, but unequal, two large and 

 two small, in the soldier. Imms ('19) has described five such en- 

 teric caeca in Archotermopsis, and states, page 165, that ''these 

 structures have not so far been detected in any other Termite." 

 The number of malpighian tubules in Termopsis is eight — the 

 same number as in Archotermopsis. 



