436 PROCEEDINGS OF THE ACADEMY OF [July, 



there is a deposit of pigment on the dorsal side of the largest 

 segments of the abdomen, and tliis color spreads and deepens 

 until, on the twelfth day, the sex of the future ant can thereby 

 be foretold, the worker-pupa being yellowish all over, the male- 

 pupa gray-bodied with white limbs, the queen-pupa mottled brown 

 and orange with yellowish limbs. Two days later the worker-pupa 

 acquires the rich dark amber color which it retains as a callow ; 

 the slate color of the male-pupa deepens to black, and the queen- 

 pupa has the tints of an adult queen. The length of the pupa- 

 stage was ascertained by me for seventy-three pupa, all presumably 

 the issue of queens' eggs, in fifteen different habitations, between 

 January 5 and May 27. I took the time from emergence from 

 the larval sheath to the assumption of the standing posture as the 

 period of pupa-existence. Forty-four of my number proved to be 

 minims, and of these two became such on the fourteenth day, 

 twenty-three on the fifteenth day, and nineteen on the sixteenth 

 day. 



Fourteen became minors, and of these eleven became such on 

 the seventeenth day and three on the eighteenth day. 



Ten became majors, and of these five became such on the nine- 

 teenth day, four on the twentieth day and one on the twenty-first 

 day. 



The pupa-stage of the sixty-eight workers varied, therefore, 

 between thirteen and twenty-two full days; but the minims may 

 be said to have a pupa-period of about fifteen days, the minors a 

 pupa-period of about seventeen days, and the majors a pupa- 

 period of about nineteen days. 



Four of the seventy-three pupte became kings, and of these one 

 became such on the eighteenth day, two on the nineteenth day 

 and one on the twentieth day. 



One only became a queen. She was a pupa nearly seventeen 

 days, and died soon after beginning to walk about among the three 

 workers that reared her from a queen's egg. 



Of some hundreds of larvte that have successfully been reared 

 to the pupa-stage by my captive ants, not more than ten have 

 failed to safely pass the pupa-stage and to live on as ants. The 

 small proportion of deaths among the ant-children, in so unnattiral 

 an environmeut as is created by a glass nest and a human pur- 

 veyor, surely indicates a more than human skill on the part of the 



