48 
Psyche 
[June 
(1934) briefly discuss this close correspondence, and con- 
clude correctly that the resemblance is superficial and due 
to convergence. The ants are obviously in separate genera. 
They consider the possibility of mimicry, with occidentalis 
serving as the model. I have exserted the stings of both 
ants, and while that of Pogonomyrmex is much stouter and 
from appearances more powerful and effective as an organ 
of defense, it is not possible with the still meagre amount 
of information we have to say that mimicry is involved. 
The rarity of lobognathus, its distributional characters, 
and its superficial divergence from other species in its 
genus do conform to Wallace’s Rules for Batesian Mimi- 
cry, but it would be premature to label the case as one 
of mimicry at this time. It may be legitimate to ask 
whether the weak stings of other myrmicine ants are 
equally ineffectual for defense, and also what reasons 
might be deduced to explain why the other members of 
Veromessor which occur in the same habitats as forms of 
Pogonomyrmex more pugnacious than occidentalis do not 
show a defensive convergence towards these latter species? 
The distribution of V. lobognathus is distinctly un- 
orthodox, almost all the rest of the species in the genus 
being confined to the southwestern deserts of Arizona, Cali- 
fornia (including the Central Valley), Lower California, 
and western Mexico. A gap of several hundred miles exists 
between the previously known records of V eromessor and 
Glenwood Springs, the type locality of lobognathus. Sev- 
eral years ago, Dr. M. R. Smith (1951) described a new 
form of this group, V. lariversi, which had been secured 
near Pyramid Lake, Nevada, and since then Dr. Creighton 
has found the species near Lone Pine, California, Wagner, 
Nevada, and Goldfield, Nevada. Thus the genus is now 
known to extend further east in the northern part of its 
range than heretofore. But this extension makes no sig- 
nificant change in the status of lobognathus whose most 
western station is in the upper reaches of the Colorado 
River Canyon at an altitude of 5,750 feet (Glenwood 
Springs), with its most recent occurence now recorded 
from the eastern slope of the Rocky Mountains at an 
elevation of 6,100 feet. From the nature of the genus and 
