LIFE HISTORY. 41 
proffer food to, or at least inspect, each larva, for the worker doing 
the feeding will place her mandibles to the mouth of one larva after 
another, feeding those which seem to require it. 
Both larvae and pupae are groomed or licked with the tongues of the 
workers; thus they are ever kept in a state of absolute cleanliness. 
The most pronounced increase in size of the larvae occurs during the 
first five days after hatching. As is the case with other ants, nothing 
is voided from the alimentary canal during the larval period, the 
undigested portions of the food being retained in the stomach, the 
latter having no open connection with the intestine. As the larva 
reaches its full growth this meconium, or mass of undigested material, 
becomes quite large and is distinctly visible as a dark object in the 
posterior portion of the body. At about this time communication is 
established between stomach and intestine and the meconium is 
voided. The larva then enters the prepupal or semipupal stage. 
While the insect in this stage is not very different in appearance from 
a full-grown larva, close examination shows a number of slight differ- 
ences. Aside from the absence of the meconium, the cephalic and 
thoracic regions become markedly smooth and shining, with segmen- 
tation very indistinct, while the segmentation in the abdominal 
region is, if anything, more pronounced than before. The line of 
demarkation between abdomen and thorax is now in evidence, but 
without any very noticeable constriction. The mouth parts are 
protruded more than in the larva. The difference in appearance 
between larval and prepupal stages is not great but is sufficient to 
enable one to predict, with reasonable accuracy, the approaching 
transformation to the pupal stage proper. 
In the later portion of the larval stage we have first been able to 
distinguish between the males and workers. The male larvae grow 
to a somewhat larger size than do the worker larvae, and it is thus 
possible to predict with some degree of certainty which of grown 
larvae will transform to males and which to workers. In all other 
respects, however, they are apparently alike. The larval stage of the 
queen is unknown to us. 
DURATION OP THE LARVAL STAGE. 
The duration of the larval period has been determined by observa- 
tion in the artificial nests in the same manner as the incubation period 
already described. 
The following table shows the duration of the larval period at dif- 
ferent seasons. 
