602 CAROLINE B. THOMPSON AND THOMAS E. SNYDER 
taking longer or shorter aerial flights, and drop to the ground; 
then, after shedding their wings and selecting their mates, the 
search for a new habitation may consume some time. The 
second-form adults do not swarm and possibly need less time for 
the establishment of the new habitation before egg laying begins. 
It should, however, be stated that it is not known with certainty . 
how the second-form adults establish new colonies. 
The young adults of the second form. The yellowish color of the 
body, the small light-brown compound eyes rimmed with white, 
and the thin scale-like appearance of the wing vestiges distin- 
guish the second-form adults externally. Since the wing pads, 
or vestiges, cease their: growth sooner than the abdominal seg- 
ments, the former are relatively shorter in the adult second form 
than in the nymph, sometimes extending only to the beginning 
of the second abdominal segment. Genital appendices are absent 
from the ninth segment of the female. The sides of the abdomen 
of young second-form adults, especially of the males, are usually 
laterally compressed, giving the specimen a ridged appearance. 
Internally the chief differences between first- and second-form 
adults are quantitative, the second form having a smaller brain, 
compound eyes, frontal gland, and sex organs. 
The venation of the wing vestiges of the second-form adult 
and the wing pads, of the second-form nymph is the same 
and homologous with that of the first-form adult and nymph. 
The rudiments of the four veins, subcosta, sc., radius, 7, media, 
m, and cubitus, cu, may be noted in figure 4, and one of the 
differences between fore. and hind wings, mentioned above, 
namely, the coalescence of the radius and media in the proximal 
part of the hind wing, is also here present. ‘There are no traces 
of the humeral suture in either wing vestige, and no signs of 
even a faint ‘radial sector’ in the hind vestige. 
The enlarged adults of the second form. These forms may 
attain a body length of 12 mm. in living specimens, but are never 
as long or as stout as those of the first form. The body color is 
yellowish rather than creamy white, with darker chitinized 
areas, as in the first forms. Very often the abdomen of the 
