1969] 
Brown and Kempf — Acanthognathus 
93 
floor of tropical forests. All of the samples for which we have 
ecological data came from moist or wet forest of the tropical or 
subtropical type. Nests of isolated (possibly nest-founding) dealate 
queens of brevicornis , lentus, ocellatus and rudis have usually been 
taken in rotten twigs or small pieces of rotting wood in forest litter. 
The colonies are small, often with only 10-20 or fewer adult workers, 
and no nests with more than about 30 workers have been seen. 
Usually there is a single dealate queen per nest, though two have 
been found in a nest of A. rudis from Sao Paulo. The nests resemble 
greatly those of certain long-mandibulate Strumigenys , as already 
noted by Mann (1922), and like Strumigenys, the Acanthognathus 
workers and queen move slowly and often curl up to play dead 
when jarred. 
An observation of Moeller, repeated by Emery (1922) and others , 
showed that workers use the basal processes of the mandibles to carry 
their brood. We have been able to confirm this activity for A. 
ocellatus and A. rudis in captive colonies. We have also observed 
these same two species to capture, by means of a snap of the mandibles, 
entomobryid Collembola that were placed in the artificial nest with 
them. A colony of A. ocellatus from Cerro Campana, Panama, fed 
a newly-captured entomobryid to a larva, after the fashion of 
Strumigenys. Limited tests of other small, soft-bodied arthropods 
were tried with both ocellatus and rudis , and though none of these 
was captured or even approached, the trials were too few to establish 
the breadth of prey specificity. Foraging workers of these two species, 
and the holotype of A. teledectus before its capture in the leaf litter, 
held their mandibles open to about 180 0 when threatened or when 
approaching prey. This is apparently accomplished by locking to- 
gether the apices of the opposed basal processes, but the details are 
not altogether clear, especially the role, if any, of the labrum in the 
process. As with Strumigenys, the sting is employed to quiet strug- 
gling prey. 
A worker of A. ocellatus taken by Markl on Trinidad is accom- 
panied by the note, “at night,” indicating what the relatively large 
eyes suggest — that foraging is epigaeic, perhaps subarboreal, and 
largely crepuscular or even nocturnal. The similar Australasian 
genus Orectognathus appears to follow this foraging pattern. 
The Species 
A canthognathus comprises six known species, of which five are 
very distinct, and one, A. lentus, is kept separate from A. ocellatus 
with doubt for the time being. 
