48 
Psyche 
[June 
this ant is very peculiar and no amount of logic applied to 
fragmentary material could have given a correct concept of 
the species. Before discussing these peculiarities it seems 
advisable to present an account of the earlier taxonomy of 
ulcerosus and bruesi. Several of the proposals carried in 
this paper depend upon previous studies on this remarkable 
insect. 
The original description of ulcerosus and that of bruesi 
were both presented in a paper by W. M. Wheeler which 
appeared in 1910 (1) . At that time the subgenera of Campo- 
notus were in a rather fluid state, hence it is not surprising 
that Wheeler made no attempt to assign either of his species 
to a particular subgenus. Instead he related bruesi to the 
novogranadensis group and left ulcerosus in a group of its 
own. It is instructive to note that Wheeler felt that ulcero- 
sus formed a link between bruesi and species in the sub- 
genus Colobopsis. Although this view is incorrect, it shows 
that Wheeler was aware of a basic structural similarity in 
the specimens which he assigned to bruesi and to ulcerosus. 
With adequate material for study the importance of this 
similarity would have been appreciated and subsequent con- 
fusion avoided. But the material upon which Wheeler based 
his original descriptions was far from adequate. There was 
a single major worker and five or six minors of bruesi, all 
strays taken by Wheeler at Ft. Davis, Texas. In addition 
to these types Wheeler had six more minor workers coming 
from two stations in Mexico. The paucity of type material 
was even more acute in the case of ulcerosus. This spe- 
cies was described from a single major worker taken by 
C. Shaeffer at Palmerlee in the Huachuca Mountains of 
Arizona. 
In both of Wheeler’s species the major worker possessed 
a striking, oblique truncation at the front of the head. But 
in the type of ulcerosus each cheek bore a large, deep, ulcer- 
like depression. The outer edge of each depression was 
bounded by a ridge along the lateral border of the head. Its 
inner edge lay close to the clypeus and the frontal lobe. 
These depressions, the clypeus and the frontal lobes were 
covered with very coarse, uneven, irregular rugae. In con- 
trast, the type of the major worker of bruesi showed no 
depressions on the cheeks. The truncated anterior part of 
