430 PKOCKEDINGS OF THE ACADEMY OF [Jllb'» 



limes for many days together. Some of the queens in my Petri 

 cells have averaged more than one egg a day during every month 

 from September to the following July, and they and their workers 

 appear to be in good health, though they have had during the 

 winter no respite from the labor of rearing the young. 



The eggs laid by the queens are visible to the unassisted eye, are 

 a pearly translucent white, and are oblong in shape, the thickness 

 being about half the length, which is half a millimeter. When 

 the queen is about to deposit an egg, workers stand about her, as 

 if aware of a new duty, aud they pick up the egg as soon as it is 

 deposited aud add it to the packet, which is constantly tended, 

 kept clean, watched over and carried about by the workers. The 

 egg -packet, after being carried about for some time by one worker, 

 is passed over to another, who appears to assume the burden 

 eagerly. If the queen is alone she takes care of her own eggs. 



In order to ascertain the time of incubation, I placed queens 

 each in a clean Petri cell, some with workers, some without workers, 

 and cleaned each cell daily until the first egg was deposited in it. 

 I examined the cell two or three times a day, and recorded the 

 time of deposit of the first egg and of a few succeeding ones. In 

 some cases I removed the queen after a few eggs had been depos- 

 ited, leaving the eggs to the care of the workers alone. I counted 

 the eggs daily to see that there was no diminution in their number, 

 aud I cast out from my calculations all cases in which there was a 

 diminution of the number of eggs during the time of my observa- 

 tions. I was also careful that there should be no manipulation nor 

 disturbance of the eggs except by the ants themselves. The eggs 

 recorded were laid between the 7th of October and the 8th of the 

 following May, aud were laid by ten diff^erent queens. Twenty- 

 two simultaneous or successive broods were thus observed, with the 

 result that in two cases the first larva appeared on the eighteenth 

 day after the laying of the first egg; in nine cases on the nine- 

 teenth day; in ten cases on the twentieth day; in one case on the 

 twenty-first day. The time of incubation was not influenced 

 solely by temperature, for eggs laid by different queens on the 

 same day did not invariably hatch on the same day. In six of 

 the twenty -two broods two eggs were deposited by the same queen 

 on the first day, and these six broods each produced its first two 

 larvre within the same day. Furthermore, the appearance of 



