532 THE AMERICAN NATURALIST. [Vor. XXXV. 
soil of the piece of land above mentioned I obtained some fine 
and very clear vertical sections of the nests of the Solenopsis. 
They consisted of small chambers of a circular form measuring 
8-20 mm. in diameter and only 6-8 mm. in height. Most of 
these chambers were at least several centimeters apart. Their 
floors were remarkably clean, smooth, and even hardened. 
They were connected by tenuous galleries, often less than 
2 mm. in diameter, entering the chambers at their ceiling, at 
their lateral walls, or at their floors, and uniting with their sur- 
faces by means of a perceptible infundibular orifice. Forel 
(74, p. 385) saw several Solenopsis leave the earth and steal in 
among a stack of cocoons which had been heaped up by some 
Formica pratensis that had been dumped on the ground. The 
Solenopsis set to work perforating the cocoons and cutting 
the pupa to pieces, thus destroying a great number of them. 
Forel is correct in his inference that the Solenopsis behave in 
the same manner in double nests. At this writing I repeat 
this observation daily on an artificial double nest of S. fugax 
and F. rufibarbis. Every day I give the Solenopsis about ten 
cocoons of Lasius queens, placing them near the entrance of 
the nest. It is not long before the Solenopsis make their 
appearance. From ten to thirty of them climb up onto each 
cocoon and cover it with little perforations, which, finally 
becoming confluent, enable them to reach its contents. If it 
contains a pupa, the legs and antennze fall an easy prey to the 
mandibles of the Solenopsis. In this case the victim is cut 
into, sucked, and torn into very small pieces, which the ants 
hasten to carry away into the interior of the nest. The opera 
tion is much more difficult if the contents is a larva which has 
just spun its cocoon, or a pseudonymph. I have seen the Sole- 
nopsis drag a larva of this kind into the interior of the nest 
and keep working at it for twenty-four hours. At the expira- 
tion of this period the larva began to look flaccid and was COV- 
ered with little black dots, which were sometimes double, cor 
responding with the little wounds made by the mandibles. 
Numbers of the Solenopsis were busy lapping up the liquid 
which exuded from the wounds, but it was not until thirty-s™ 
hours had elapsed that the larva was entirely devoured. Large 
