1962 ] 
Wilson — Erebo/nyr/na 
65 
seems a fairly safe conjecture that longi soldiers will be discovered 
when whole colonies of that species are collected. 
As just noted, the Oropouche uric hi and a colony taken at Bern- 
hardsdorp, Surinam, are considered conspeeific. 1 he minor workers 
of the two colonies are virtually identical. In the Oropouche soldier 
the anterior face of the petiolar node is slightly more inclined posteri- 
orly (thus forming a greater angle with its anterior peduncle), the 
anterodorsal nodal angle somewhat more rounded, the propodeal 
angles are more pronounced and acute, and there are some differences 
in thoracic form and sculpturing (see text-figure). I he Oropouche 
queens have slightly more developed propodeal spines and larger ocelli. 
In other respects the soldiers and queens appear identical between the 
two colonies. 
Together, the Trinidad and Surinam uric hi differ markedly from 
those in a series of Erebo/nyr/na collected recently at Barro Colorado 
(W. L. Brown and E. S. McCluskey leg.) and tentatively determined 
as nevermanni Mann. The urichi minor worker has distinctly nar- 
rower, more erect propodeal spines; while the urichi soldier is much 
smaller and with more pronounced propodeal spines (text-figure). 
Ecology 
Trinidad. The Oropouche Cave is the source of the Oropouche 
River, which extends back into th£ cave as a clear stream several 
meters in width. A colony of Erebo/nyr/na urichi was found approxi- 
mately 30 meters inside the cave on the bank of the stream, in very 
feeble light coming from the plainly visible cave mouth. Much of the 
ground was covered by guano dropped from the large numbers of 
guacharos nesting overhead. The arthropod fauna at this point was 
rich and diverse, consisting of ants [Mesofionrera constricta Mayr, 
Odonto/nachus haematodus (Linne), and Solenopsis (Diplorhoptrum.) 
tenuis Mayr], as well as the Erebo/nyr/na entomobryid collembolans, 
cave crickets, dermapterans, small flies, and mites. The ant species, 
other than Erebo/nyr/na, have been collected outside caves in Trinidad. 
Mesoponera constricta , which was the most common forager in the 
vicinity of the Erebo/nyr/na nest, was also a dominant ant along the 
trails through cacao plantations in the Cumaca area. Most of the 
other insects appeared to be troglophiles. Fifteen meters farther in, 
and in almost total darkness, a large Bufo marinus was found. In 
short, at the site of the first Erebo/nyr/na nest, troglophilic (faculta- 
tively cavernicolous) animals predominated. 
A second group of foraging Erebo/nyr/na workers, almost certainly 
