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Psyche 
[March 
eversion occur with some consistency. Reluctance to employ the 
glands in these animals is undoubtedly related to their possession of 
a particularly tough integument, which may in itself provide an ef- 
fective first line of defense. 
In order to observe more precisely the method of employ of the 
glands, individual A . percatum were affixed to wire tethers with wax, 
and stimulated by pinching their legs with forceps. The beetles were 
Sometimes placed over filter paper impregnated with an acidified 
aqueous solution of potassium iodide and starch, a mixture that dis- 
colors darkly on exposure to benzoquinones (Roth, 1943) and pro- 
vides a good visual means for detecting secretory emissions. The 
results were identical with all nine specimens tested. Stimulation of 
a single leg generally caused extrusion of only the gland of the corre- 
sponding side (Figs. 3-6). Simultaneous stimulation of two legs 
caused bilateral eversion. The extent and rapidity of extrusion varied, 
and seemed to depend on the intensity of stimulation. A brief squeeze 
of a hindleg or midleg, for example, usually induced only a partial 
eversion of the ipsilateral gland. Protracted or more vigorous squeez- 
ing elicited more complete and usually sustained eversion, and the 
extruded gland commonly extended outward far enough to contact 
the seized leg or forceps (Figs. 3-5). The target was usually visibly 
wetted by the gland. The beetles can apparently exercise some con- 
trol over the direction of extrusion. Thus, when distal parts of a 
hindleg were stimulated, the gland usually extended outward at a 
greater angle relative to body axis than when more proximal parts of 
the leg were grasped. The gland is apparently aimed by flexion at its 
base rather than along its length, as evidenced by the fact that its 
shape is relatively fixed irrespective of its angle of protrusion. 
When gland eversion occurred abruptly rather than gradually, as 
was generally the case in response to vigorous pinching, the sudden 
extension of the gland sometimes caused secretion to be ejected 
forcibly as a spray. (Figs. 6, 7). Ejections ranged from 1 to 5 cm, 
but in one instance droplets were shot to as far as 25 cm from the 
beetle. Forelegs and such other parts on the front of a beetle as are 
ordinarily inaccessible to the glands were inevitably doused by such 
ejections. Only beetles with replete or nearly replete glands tended 
to spray. However, animals with partly depleted glands could still 
effectively administer secretion to their front end. They did this by 
relaying secretion from one pair of legs to another, following initial 
wetting of the hindlegs by the glands. Even the antennae and the 
head itself were eventually wetted with secretion if they had been 
