WINGLESS REPRODUCTIVE TYPE OF TERMITES 625 
CONCLUSIONS AND SUMMARY 
A general study of the termites Reticulitermes flavipes, R. 
virginicus, and Prorhinotermes simplex establishes the fact of 
the existence in each of five well-marked types or castes, three 
reproductive and two sterile, namely: 1) adults of the first form, 
with long wings; 2) adults of the second form, with wing vestiges; 
3) adults of the third form, with no wings; 4) the workers, and, 
5) the soldiers. 
Throughout these series of forms there is a correlation in the 
size, structure, and degree of development of the brain, the eyes, 
and the sex organs; and, in general, there is a gradation in the 
size of these organs from the first form down to the worker or 
soldier, this gradation of structure possibly representing different 
degrees of retrogressive ancestral mutations. On the other 
hand, certain types possess characters peculiar to themselves, 
which may represent progressive mutations, for example, the 
stouter legs of the second forms, the thicker chitin of the head 
of the workers and soldiers, and the elongated head and mandibles 
of the latter. The type of venation found in the wings of the 
first-form adult, namely, the presence of the subcosta, radius, 
media, and cubitus, is also found in the wing pads of nymphs 
of the first and second form, and in the wing vestiges of second- 
form adults, but no trace of the humeral suture is present in 
either wing pads or wing vestiges. 
The enlarged adults of the third form of Reticulitermes flavipes 
have been known since 1915, but the young adults and nymphs 
are here described for the first time. 
In size, general shape, and absence of wings, the nearly mature 
third-form nymphs and the young third-form adults of R. 
flavipes bear a strong resemblance to workers, but the two 
castes may be distinguished by the following external characters: 
color of head, number of antennal segments, size of compound 
eyes, presence or absence of ocelli, form and color of abdomen. 
Additional differences are found in internal structures, such as 
the larger brain and salivary glands, the functional sex organs, 
the abundant fatty tissue, and the degenerate (adult) jaw muscles 
