512 CAROLINE BURLING THOMPSON 



In the enlarged dealated males, 12 to 14 mm. long (fig. 15), the 

 testes, t, are slightly smaller, especially in the very oldest in- 

 dividuals, than in the mature nymphs of the first form (fig. 16). 

 This is due to the shrinkage of the organ as most of its component 

 sex cells become transformed into spermatozoa and pass out into 

 the vas deferens, leaving behind eventually only connective- 

 tissue cells. The vasa deferentia are firm though slender, with 

 a definite lumen and are connected with the base of the seminal 

 vesicles on their dorsal surface. The seminal vesicles, sv, are 

 greatly branched and convoluted, each tubule being broader and 

 more expanded than in the mature nymph. No spermatozoa 

 were found within the seminal vesicles of males of any age or 

 caste, and the lumen is filled by a fluid secretion, staining yellow 

 with iron haematoxylin and orange G. This shows that the semi- 

 nal vesicles of Termopsis are glandular in function, and doubtless 

 homologous with the colleterial glands of the female. 



Sections of the testes of the older males of the first form show 

 the central space and the proximal portions of most lobes filled 

 with masses of metamorphosing spermatids and mature sperma- 

 tozoa in tangled clumps, not in packets. In the oldest individuals 

 very few spermatogonia remain in the distal ends of the lobes, and 

 there are many empty spaces crossed only by strands of connec- 

 tive tissue. The tubes of the seminal vesicles have a larger lumen 

 and a more copious secretion than in the nymphs. 



The fat-body in very old individuals is still large, but is no 

 longer a solid mass, and contains more empty spaces than in the 

 nymphs and young adults. 



THE SECOND FORM OF T. ANGUSTICOLLIS 



Second-form individuals of T. angusticolUs, with very minute 

 wing vestiges (fig. 6), are at present considered rare, and speci- 

 mens have been recognized with certainty only in the young adult 

 and enlarged adult phases. The writer is inchned to believe, 

 however, that this caste is less rare than has been supposed, and 

 that it has been mistaken on the one hand for a young nymphal 

 phase of the first form and on the other for an adult of the third 

 form. Specimens frequently have one or more of the tiny wing 



