106 
Psyche 
[December 
checks with observed facts it is far from satisfactory as an 
explanation covering the death of the Brachymyrmex. We 
may admit that most ants are severely affected by injuries 
involving the antennae but it rarely happens that such in- 
juries are immediately followed by death. The loss of a 
tarsal joint or two is usually a matter of slight consequence. 
Yet in thirteen cases injuries of the nature just described 
were accompanied by the rapid demise of the victim. Again 
I find myself led to the view that some substance is ejected 
by the Strumigenys as they strike at the victim. It would 
seem necessary to believe that this substance is not only 
Fig. 1. Cephalic structures of Strumigenys louisianae subsp. 
laticephala Smith. For explanation of figures see text. 
irritating but toxic. Again I must stress the fact that I 
cannot prove this assumption. It is, however, the only 
explanation which appears to cover the facts. 
I wish to add a few more observations concerning the 
manner in which the Strumigenys workers use their man- 
dibles. The first of these involves a detailed discussion of 
the role of the mandible during attack, a matter which is 
more complex than might be supposed. The extreme rapidity 
with which the mandibles are closed in striking makes this 
process very difficult to follow. Repeated observations have, 
