1901.] NATURAL SCIENCES OF PHILADELPHIA. 435 



stage, the larva expels the contents of the alimentary canal, ceases 

 to feed, and changes in color from translucent white with a brown 

 core to creamy and more opaque white. Deprivation of food for 

 some days will cause any half-grown larva to make these prepai*a- 

 tions for becoming a pupa, and minims can be reared at will. 



The larva; are kept resplendently clean by the licking given by 

 the workers. In my nests the workers appeared lo learn a use 

 for the sponge, and when I at various times soiled a larva with 

 stale insect juices, they rubbed it upon the sponge to clean away 

 what they apparently disliked to lick off'. 



Either majors, minors, or minims alone can feed larva?, but in ray 

 Petri cells, where food is always near, they have rarely reared 

 more than three larvae to each adult worker. A minim alone with 

 a queen reared three larvse simultaneously, and five majors together 

 reared sixteen. The anxiety which impels the nurses to lift the 

 immature young whenever the cell is uncovered probably hinders 

 their rearing large numbers in these abodes. When disturbed, 

 the workers first lift the oldest in the nest, the pupte, the larvje or 

 the egg-packet. This order is also followed by the solitary queens. 



After the larvae are large enough to be removed from among 

 the eggs of a packet and to lie separately on the floor, they are so 

 fed as to bring them to about the same size. As the eggs are laid 

 rather regularly, one or two a day, and are nearly equal in their 

 periods of incubation, the larvte, if evenly fed, would reach the 

 pupa stage one by one. But great naturaL possibilities of shorten- 

 ing or prolonging the larval period by increase or diminution of 

 the supplied nutriment, and the method of feeding the larva? so 

 unequally as to keep them nearly equal in size, causes the normal 

 nest to be at times without pupa?, and at times to be destitute of 

 advanced larvte. I have observed in natural nests, and also in my 

 artificial nests, that at times there are a great number of larva? 

 and no pupse, and at times countless pupa? with no advanced 

 larvie. 



The larva? grow to the length of the pupa? perfected within their 

 integument, varying from two to five millimeters. When the thin, 

 transparent-white integument bursts, the ants clean the snow-white 

 naked pupa, and constantly watch over and tend it. Its first color 

 appears in the eye-spots, which are grayish on the third day and 

 brown on the fifth. On the tenth day, with the utmost regularity. 



