1963] Blum and Callahan — Glands of Pseudomyrmex 
73 
The skin response at the sting site is characterized by the immediate 
development of a flare, which reaches its maximum size in five to 
ten minutes. This is rapidly followed by the development of a wheal 
at the point where the lancets entered the skin. Within one hour the 
flare disappears and the area is marked only by the wheal which may 
persist for up to 24 hours. A, dull pain is present after the ant has 
stung which becomes less intense within the first hour. A throbbing 
sensation is evident during this time which diminishes in intensity 
until by the end of the second hour very little discomfort is evident. 
Mild prurience is evident for at least 24 hours during which time a 
prominence develops at the site of the sting. This elevation is sur- 
rounded by a narrow red halo. After 48 hours, the puncture area 
is characteristically umbilicated and the depressed center is discolored, 
a condition which may persist for up to two weeks. 
Discussion 
One of the most significant characteristics about the venom of 
P. pallidus is that it is proteinaceous. Among the other stinging ants, 
only the myrmicine genus Solenopsis has been studied and it has been 
demonstrated that the venom is a non-protein (Blum et al. 1958; 
i960). Thus, this pseudomyrmicine species is similar to vespid wasps 
and the honey bee in producing biologically active proteins in their 
poison glands whereas Solenopsis , a phylogenetically advanced myr- 
micine genus, differs in that its venom is non-proteinaceous. 
The subfamily Pseudomyrmicinae is a relatively primitive one 
(Brown 1954) and it is tempting to speculate that proteinaceous 
venoms are characteristic of the more primitive subfamilies of ants. 
In support of this idea is the fact that the venoms of ponerine and 
doryline species that we have examined in our laboratories are pro- 
teinaceous. Along with the Pseudomyrmicinae , these families are more 
primitive than the Myrmicinae. In our laboratories, analyses of the 
venoms of the less highly developed myrmicines are now being carried 
out in order to determine whether or not this subfamily contains 
genera producing proteinaceous venoms as well. 
It will of course be necessary to examine the venoms of many genera 
of ants in all subfamilies in order to determine whether or not pro- 
teins are limited to the phylogenetically less developed ones. It is 
well established that in the highly developed subfamily Formicinae, 
the poison glands produce the simple fatty acid formate, a considerable 
departure from the complexity of the proteinaceous or nitrogenous 
base-containing venoms found in Pseudomyrmex and Solenopsis 
respectively. 
