1963 ] Eisner , Hurst and Meinwald — Defense Mechanisms 105 
were from Ocean Beach Drive, S. C. ; the blue jay was a laboratory- 
reared individual from Ithaca, N. Y., and the lizard and mouse 
stemmed from Arizona. Tape recordings were made of running 
commentaries delivered while witnessing the encounters, and these 
recordings provided the basis for the measurements of time intervals 
and other quantitative data given below. The scarcity of Chlaenius 
and Abacion limited the number of tests that were possible. 
a. Pogonomyrmex badius (Latreille) 
1. Versus Chlaenius. 
The experimental conditions were similar to those that prevailed 
in tests with this same ant and certain other beetles, cockroaches and 
earwigs that also spray (Eisner 1958a, 1958b, 1960a). Individual 
beetles, affixed to rods, were placed one at a time just outside the 
nest entrance of a laboratory colony of Pogonomyrmex. The results 
were essentially the same with each beetle. The ants attacked 
immediately, converging upon the beetle in groups, grasping it with 
the mandibles while pointing their gasters forward in stinging posi- 
tion. Suddenly, within no more than a few seconds after initiation 
of the attack, the entire swarm dispersed. The ants fled aimlessly and 
quickly, pausing frequently for brief spells of intense cleansing activity. 
Their escape and cleansing behavior was identical in all major respects 
to that shown by this and other ants in response to arthropod secre- 
tions containing acids and quinones (Eisner, 1958a, 1958b, 1960a; 
Eisner et. al., 1961). Within one to several minutes after discharge, 
the ants seemed to have recovered completely, and had resumed their 
normal ambulatory pace. There were, however, no immediate new 
attacks. For 8 to 13 minutes after a discharge, the beetle remained 
invulnerable. Ants coming to within its immediate vicinity turned 
about abruptly and walked away, apparently repelled by residual 
secretion and its vapors. Some of this residual secretion must have 
EXPLANATION OF PLATE 11 
Fig. 1. Chlaenius cordicollis Kirby. 
Fig. 2. Excised gland of Chlaenius. A, racemose cluster of gland cells; B, 
efferent duct; C, reservoir; D, ejaculatory duct. 
Fig. 3. Grasshopper mouse eating Chlaenius (for details, see text, part 
m) . 
Fig. 4. Terminal portion of ejaculatory duct and associated musculature of 
a Chlaenius gland. A, the short flat muscle that effects nozzle extrusion; B, 
the muscle that forces apart the terminal cuticular valve of the duct, thus 
freeing the lumen for nozzle extrusion; C, ejaculatory duct, invested by circu- 
lar muscles; D, level at which circular muscles come to an abrupt halt; E, 
naked portion of ejaculatory duct; F, partly extruded spray nozzle (extrusion 
was aoDarently caused by shrinkage of muscles resulting from histological 
fixation). 
