40 THE ARGENTINE ANT. 
THE LARVA. 
(PL IV, B, C.) 
The larva when first hatched is not distinguishable from the egg 
without the assistance of a magnifying glass. For a time after 
hatching the body is considerably curved, the cephalic end being 
almost in touch with the caudal end, but as development progresses 
the larva assumes more and more of a straight form. The curvature 
is not entirely lost, however. 
A recently hatched larva, measured with the compound microscope 
and eyepiece micrometer, was 0.49 mm. long by 0.32 wide. The fully 
grown larvae (workers) average 1.7 mm. long by 0.66 mm. wide. The 
largest one under our observation measured 1.87 mm. by 0.765 mm. 
With the exception of slight constrictions of the body, the larvae 
are incapable of motion, thus being entirely helpless and relying 
altogether upon the ministrations of the attendant workers. The 
latter, however, perform their duties faithfully, and care for their 
charges with the greatest solicitude. They feed and groom the 
young larvae continually and transport them from place to place 
whenever necessary. In case of danger their first instinct appears to 
be to remove the young to a place of safety, and they readily sacrifice 
their own lives in order to accomplish this. 
The larvae are fed often by the attending workers upon regurgitated 
and presumably predigested food. There is nothing in the appear- 
ance or actions of the workers which do the feeding to indicate that 
they are different from those which perform other duties, or that 
they are assigned to the particular and exclusive duty of being nurses. 
The feeding of the larvae has several times been observed under a 
magnifying glass, and is as follows: The larva ordinarily lies upon 
its side or back. The attending worker approaches from any con- 
venient direction, usually from one side or from the direction in which 
the head of the larva lies, and, spreading her mandibles, places them 
over the mouth parts of the larva, which are slightly extruded. The 
tongue of the worker is also in contact with the larval mouth. While 
the worker holds the body and mandibles stationary a drop of light- 
colored, almost transparent fluid appears upon her tongue. This 
fluid disappears within the mouth of the larva, but it can not be ascer- 
tained to what extent the larval mouth parts are moved during the 
operation, as they are obscured from view by the mandibles and head 
of the attending worker. Slight constrictions of the larval abdomen 
during feeding are sometimes noticeable, at other times not. The 
time required for feeding a single larva varies from 3 to 30 seconds, 
depending doubtless on the hunger of the "baby." The workers 
