LIFE HISTORY. 
43 
In some colonies there is more or less of an indistinct sorting of the 
immature stages, pupae being placed in one portion of the nest and 
larvae in another. This tendency is not perceptible in many colonies 
and is usually most noticeable in very large colonies. 
The duration of the pupal stage has been determined in the manner 
already described for the incubation and larval periods. The range 
of pupal development is shown in the following table: 
Table IV. — Duration of pupal stage of the Argentine ant, individual workers, 1908-9. 
Record No. 
From — 
To— 
Days. 1 
Average 
daily 
mean 
tempera- 
ture 
during 
period. 
Average 
daily 
mean 
humid- 
ity. 
1 
Jan. 21,1908 
Mar. 14,1908 
Mar. 26,1908 
Mar. 30,1908 
Apr. 5,1908 
do 
Feb. 14,1908 
Mar. 27,1908 
Apr. 11,1908 
Apr. 14,1908 
Apr. 15,1908 
Apr. 18,1908 
Apr. 20,1908 
Apr. 23,1908 
May 13,1908 
May 14,1908 
Aug. 11,1908 
Aug. 16,1988 
Aug. 20,1908 
Sept. 7,1908 
Apr. 28,1909 
June 22,1909 
July 6, 1909 
25 
14 
17 
10 
11 
14 
16 
16 
19 
20 
11 
11 
11 
11 
24 
10 
m 
° F. 
56.5 
67.5 
73.8 
73.8 
76 
76.3 
76.7 
76.6 
71 
71.2 
82.2 
83 
82.8 
81.4 
70.1 
82.75 
84.08 
Per cent. 
68.3 
2... 
71.8 
68.9 
G... 
70.2 
3 
73.5 
10 
74 
7 . . . *. 
do 
74 
8... 
Apr. 8, 1908 
Apr. 25,1908 
do 
74.5 
9 
63.5 
11. 
61.4 
4 
Aug. 1,1908 
Aug. 0, 1908 
Aug. 10,1908 
Aug. 28,1908 
Apr. 5,1909 
June 13,1909 
June 24,1909 
80 
12 
74.8 
13 
70.7 
14 .. 
71 
19 
68.4 
21 .. 
68.75 
22 
76.08 
1 Average days, 15. 
THE MALE PUPA. 
(PI. IV, at center.) 
The male pupa is fully 50 per cent larger than the worker pupa and 
has, by comparison, an enormous thorax. The male pupae vary in 
length from 2.78 to 3.23 mm., with an average length of 3.04 mm. 1 
As the average length of the thorax alone is 1.19 mm., it is at once 
seen what a relatively large part of the body it constitutes. The male 
pupa is shown in the center of Plate IV. 
When first transformed from the larval stage the male pupa is pure 
white, with exception of the compound eyes, which are faintly tinged 
with brown. Gradually the color of the compound eyes deepens and 
the ocelli become visible as minute dark spots upon the head. The 
male pupa, like the worker pupa, passes through gradations of creamy 
yellow, light brown, and dark brown to almost black before transform- 
ing to the adult stage. The color reached by the male pupa just prior 
to transformation is much deeper than that attained by worker pupa?. 
The males are assisted in their transformation to the adult stage by 
1 From measurements of 10 specimens by Mr. Arthur H. Rosenfeld. 
