8 BULLETIN 3877, U. 8. DEPARTMENT OF AGRICULTURE, 
The workers feed and cleanse the larve, moving them about with 
the fluctuations of temperature and humidity to the most desirable 
places within the nest. The full-grown worker larva is about 1.5 
mm. long by 0.65 mm. wide. The average larval period throughout 
the summer months under normal conditions is about 13 days. 
PUPA. 
When the pupal stage is reached the sex of the individual is 
readily distinguishable. The pupa is white, with the exception of 
two distinct black eyespots on the sides of the head. The worker 
pupa is about 2 mm. long, the head and thorax being the larger part 
of it. The male pupa is about 50 per cent larger than the worker 
pupa, and the queen is still larger. The two latter forms may be 
readily distinguished from the worker pupa. The male pupa has 
a very large thorax and a small, closely coupled abdomen, while the 
queen pupa is much more symmetrical, the thorax is not so large, 
and the abdomen much larger than that of the male. The pedicel 
between the thorax and abdomen of the queen pupa is more con- 
stricted and elongated than in the male pupa. 
After the first few days the color of the pupa gradually changes 
to creamy yellow and continues to darken until a light-brown color is 
reached just previous to emergence. 
The duration of the pupal stage of the worker throughout the 
summer months averages about 13 days, while that of the male is 
about 22 days. No records have been established of the duration of 
the pupal period of the queen. | 
The pupe of all the stages are aided in transformation by the work- 
ers. Upon first emerging the adult is of a light-brown color which 
gradually grows darker until the second day, when it becomes indis- 
tinguishable from other adults. 
DEVELOPMENTAL PERIOD. 
By compounding the average periods of development of the egg, 
larva, and pupa, a general average of 40 days results, which repre- 
sents the complete development from egg to adult in the case of 
the worker and a somewhat longer period for the males and queens. 
ADULT FORMS. 
The worker is about 2.5 mm. in length and of a dark-brown color, 
and there is only one caste. The workers forage for food, attend the 
queen and the young, and fight to protect the colony. A large per- 
centage of the workers stay within the nest at all times and are 
always ready for any emergency, whether it be to fight invaders or 
to hurriedly seize the immature stages and retreat to securer locations 
upon the slightest indications of rain or flood. 
