42 
THE ARGENTINE ANT. 
Table III. — Duration of larval stage of the Argentine ant at different seasons- 
worker. 
Average 
daily 
Average 
mean 
daily 
Record No. 
From— 
To— 
Days. 1 
tempera- 
ture 
during 
period. 
mean 
humid- 
ity. 
° F. 
Per cent. 
1 
Nov. 16,1907 
Jan. 15,1908 
61 
52.2 
6 
Feb. 5,1908 
Apr. 1, 1908 
do 
57 
62.2 
71 9 
8 
do 
57 
62.2 
71.9 
10 
Feb. 15,1908 
Mar. 28,1908 
43 
62 
72 
3 
Feb. 29,1908 
Apr. 10,1908 
Apr. 12,1908 
July 19,1908 
Aug. 13,1908 
Sept. 4,1908 
Mar. 26,1908 
Apr. 24,1908 
Apr. 25,1908 
Aug. 1,1908 
Aug. 27,1908 
Sept. 14, 1908 
27 
67 
73 
9 
15 
76.6 
75.3 
7 
14 
76.1 
75.2 
2... 
14 
80.5 
82 
11 
15 
81.7 
71.7 
4 
11 
81.1 
73.6 
i Average days, 31.4. 
THE PUPA. 
When the pupal stage is reached by the young ant all doubt is 
removed as to the sex of the individual, for one can tell at a glance 
which pupae will transform into adult workers, which to males, and 
which to queens. The pupae of these three forms are easily distin- 
guishable and will be discussed in the order named. 
THE WORKER PUPA 
(PI. IV, B, D.) 
The worker pupa immediately after transformation from the larval 
stage is pure white, without markings, except that the compound eyes 
are prominent as jet-black spots upon the head. The pupa is 
slightly larger than the grown larva, the average length being about 
2 mm. The head is by far the most prominent portion. A pupa 
measuring 2.04 mm. in length was found to have a head 1.19 mm. in 
length (dorso-ventral diameter), while the thorax and abdomen 
measured 0.51 and 0.561 mm., respectively. 
As time for transformation to adult approaches the pupa changes to 
a creamy color, then through a light brown to a dark brown, the latter 
shade being almost as dark as the body color of mature workers. The 
time of these changes varies with the duration of the pupal stage, but 
the following record of changes in color of a pupa which occupied a 
full 20 days from larva to adult (callow), is near the average: 
First to seventeenth day — Pupa pure white, except compound eyes. 
Eighteenth day — Turned to a light creamy yellow. 
Nineteenth day — Became a light brown. 
Twentieth day — The brown color deepened. 
Twenty-first day — Reached teneral stage. 
