288 HENRY C. MCCOOK. 



effort to save the cocoons; the workers, without di.-^tinct!on, cng-aged 

 in this duty. I am not now able to say whether the ants ob:^crvecl 

 carrying the cutting of trees upon which they were working, were of 

 all ranks, but have the impression that they were.* . 



Within the formicary were stored many cocoons and a few larvae. 

 The cocoons are of a dark straw color, except a very few which are 

 white. I opened a number, and found several to contain- males, but 

 most of them workers. The dwarfs were the most numerous rank, 

 being, in ooe box examined, as thirty to fifty. In size the cocoons 

 correspond to the imago of corresponding rank and sex, the dwarf 

 cocoons averaging about one-fourth of an inch, the others about three- 

 eighths of an inch. The worker majors next to the dwarfs were most 

 numerous. No females were found within cocoons. The position 

 of the pupa within the envelope is about as follows — The head 

 is bent forward and downward upon the sternum, the legs drawn 

 up, the femur of the first leg along the side of the head, and the other 

 legs drawn np nearly parallel thereto. The remaining joints are 

 stretched along and beneath the abdomen, the last leg reaching down 

 to the apex. The antennae extend over the legs downward. In the 

 males the wings appear in a thick fold apparently enclosed within a 

 gauze-like sack, pressed against the thorax between the tibias of the 

 second and third pair of legs. The head and forepart of the body 

 when the pupae were first taken (August 22d), were whitish, the ab- 

 domen tinged with brown. The color deepened day by day, and at 

 the end of a month became a deep T'rown and black. This change 

 occurred in a young worker just delivered from the shell in one week, 

 the ant turning from pale to normal black. The eye appears black 

 and prominent upon the white face of the young pupa. 



Of a number of cocoons kept for observation, some remained alive 

 until September 24th, a period of thirty-four days. No observation 

 was made between the above date and October 4th, at which time all 

 were dead. The vitality of the pupa could always be noted by touch- 

 ing the cocoon, whereupon a vigorous motion ensued. This motion 

 would often begin as soon as the box was opened, but almost invariably 

 when the cocoon was stroked gently. It is doubtless this motion which 

 notifies the nurses of the proper time for opening the shell. A cocoon 

 of F. J^nnsi/lvanicu was placed in a jar with a worker of F. rvfa. The 

 latter was immediately attracted by the agitation within the silken 

 ijhcll, stroked the cocoon with her antennae, seized it with her jaws as 



*This fact I hope to determine next summer; also whether the dwarf is 

 capable of cutting. Its mandibles are similar in structure to the larger ranks., 

 but of course smullcr. 



