LIFE HISTORY. 41 



proffer food to, or at least inspect, each larva, for the worker doing 

 the feeding will j^lace her mandibles to the mouth of one larva after 

 another, feeding those which seem to require it. 



Both larvte 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 distmctly 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 fi'om the absence of the meconium, the cephalic and 

 thoracic regions become markedly smooth and shining, wath segmen- 

 tation very mdistinct, while the segmentation in the abdominal 

 region is, if anything, more pronounced than before. The line of 

 demarkation between abdomen and thorax is now m 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 certamty 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 OF 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. 



