394 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1921. 



shown that the food pellets taken from their pouches usually contain 

 fragments of insects, pollen of various plants, and portions of Beltian 

 bodies from the tips of the leaflets of the host plant. Larvae of this 



genus are shown herewith (fig. 7). They are 

 straight and cylindrical, rounded at each end, 

 and composed of sharply defined segments, 

 with a tough transparent skin, large squarish 

 head, and stout mandibles. The most interest- 

 ing feature of all is the food pouch, or tro- 

 phothylax, borne on the first segment of what 

 will eventually become the abdomen of the 

 ant. From this pouch, which opens toward 

 the mouth parts, the food pellets to be 

 analyzed were taken. 12 



In conclusion I would call attention to the 

 great work of Professor Wheeler, "Ants, their 

 structure, development, and behavior," issued 

 by the Columbia University Press in 1913, and to his more recent 

 and equally fascinating articles on " Social life among the insects," 

 appearing in the Scientific Monthly, beginning June, 1922. 



FlG. 7. — Larva of an aca- 

 cia ant, Pseudonujrma 

 gracilis, showing food- 

 pouch, or trophothylax. 

 Enlarged. After Whee- 

 ler and Bailey. 



13 See W. M. Wheeler and I. W. Bailey. The Feeding habits of Pseudomyrmine and 

 other ants. Trans. Am. Philosophical Society. 235-279. 1920. 



