528 THE AMERICAN NATURALIST. (Vor. XXXV. 
species which I have enumerated occur also under other con- 
ditions in the neighborhood of Cuernavaca. Nos. 1, 2, 3, and 
7 were found nesting in the dead trunks and branches. No.2 
also nests under stones, and it is probable that 4, 5, and 6, at 
least occasionally, nest in dead wood, like many other species 
of the same genera in other regions. The little Cremasto- 
gaster uses a black, paper-like substance for constructing per- 
forated partitions within the spaces which it inhabits and for 
closing up the openings left at the tops of the chambers by the 
slightly divaricating leaves of the tillandsia. A colony of this 
species was also found inhabiting the cup-like cavity of one of 
the peculiar flower-like excrescences on the branches of the 
guava trees — the “flores de guavera” of the inhabitants of 
Cuernavaca. The ants had closed the wide orifice of the cup 
with a layer of the black papery substance and had left a small 
opening near its center to serve as an entrance. The relations 
of the ants to the tillandsia would seem, therefore, to be very 
similar to those often formed by several other species with empty 
galls and hollow thorns, both in Mexico and other countries. 
These relations are of great interest as one of many expressions 
of the remarkable plasticity of instinct in these insects. 
Living colonies of Cremastogaster brevispinosa and Crypto- 
cerus aztecus were brought back to Austin and confined 
together in a Fielde nest! Although the two colonies took 
up their habitation in different parts of the same chamber, 
they were never seen to quarrel with each other. On one 
occasion some of the Cremastogasters even ventured to lick 
the red, saucer-shaped heads of the Cryptocerus soldiers ! 
III. CLEPTOBIOSIS. 
Those ants which live in or near the nests of other species 
and prey on the larvae or pupa, or surreptitiously consume 
! This artificial nest invented by Miss Adele M. Fielde ('00) is superior to any 
other that I have used. It requires closer attention than the Janet 
ests are easily 
is excellent, the closest inspection of the ants is possible, and the n 
handled, transported, and cleaned. 
