612 CAROLINE B. THOMPSON AND THOMAS E. SNYDER 
the male (fig. 29), the single ectodermal fundament, the future 
ejaculatory duct of the reproductive form, has fused with the 
mesodermal fundament of the seminal vesicles and testes, but 
growth has not proceeded beyond an embryonic phase. 
The soldier of R. flavipes 
The soldier, like the worker, is found only in the nymphal and 
adult phases 
The early development is parallel with that of the worker, both 
castes existing side by side as worker-like nymphs with round 
heads until they are a little over 4 mm. long, at which period 
the soldier nymphs molt from their worker-like skins, emerging 
as young round-headed soldiers. The elongated heads are 
acquired after a later molt. 
The adult soldier, 6 to 7 mm. long (fig. 8), has an elongated 
head covered with thick yellowish chitin. The mandibles are 
dark brown, and are long, slender, and curved, differing from the 
mandibles of the other castes. The vestigial compound eyes 
can be seen only with the microscope. The opening of the frontal 
gland is evident on the frontal surface of the head. The thorax 
is entirely wingless. The abdomen is rather short and flattened 
horizontally; it lacks the large fat masses of the reproductive 
castes and is consequently transparent. Genital appendices 
are present on the ninth abdominal segment of both sexes. 
Internally (fig. 8), the brain and the compound eyes are the 
smallest of any caste, and lateral ocelli are lacking, the frontal 
gland is large and functional. In the female (fig. 28) the three 
fundaments of the reproductive system show the same lack of 
fusion as in the worker, again representing an embryonic stage 
of development. The ovaries are the smallest of any caste of 
this species. In the male (fig. 30) the two fundaments have 
fused, but the size of the organs indicates that they are not 
functional. The testes are small, the vasa deferentia straight 
and the seminal vesicles are not convoluted. An embryonic 
penis is present which was not noted in the male worker. The 
condition of the reproductive organs of both sexes indicates that 
the soldiers of R. flavipes are incapable of sexual reproduction. 
