1957] 
Weber — Cephalotes atratus 
67 
branch. When the nests were exposed the ants remained 
motionless, appressed to the branch, or fled. 
On September 14, 3 :30 p.m., several small groups of 
ants were resting quietly on main branches of the Cassia . 
Their mandibles were not moving and they were not feed- 
ing. Aggregates like this at this time of day were not 
seen when the colony was larger. On October 2 a cluster 
of 31 was on the sunny side of the Cassia trunk at 8 a.m. 
They were watched for half an hour and showed no ten- 
dency to leave or to feed. For the most part they remained 
motionless but occasionally one would change position. On 
both dates the ants instantly dropped off when they were 
approached with the fingers. 
At all times of the year activity outside the nest ceased 
shortly before sunset, when the saman and Cassia bipin- 
nate leaves folded and drooped down, and was resumed at 
dawn. 
Behavior with Brood and Membracids 
When the brood was exposed during the first months 
many of the workers tried to carry it away. There was 
no division of labor on the basis of worker size or normal 
or anomalous morphology. An egg or small larva would 
be held by the middle, between the mandibles, and carried 
under the massive head. A larger larva or a pupa, how- 
ever, would be grasped tightly towards one end and carried 
vertically in front of the worker or even inclined over the 
back. The workers assisted the callow from its pupal case 
by cutting this with their mandibles as noted earlier. 
When the brood was exposed in later and smaller auxiliary 
nests the same behavior was noted despite the change in 
aggressiveness. 
The membracids were not defended nor taken away by 
the ants when attempts were made to collect both. At all 
times, when feeding membracids and ants were approached, 
the ants and the adult female membracids fled, the latter 
taking flight, while the nymphs were left unguarded. 
Behavior of Anomalies 
The anomalous workers behaved as normal workers. 
They were aggressive when the rest of the colony was 
