Autotomy in Phasmide. 477 
possible, and the loss of blood had been insignificant. The 
ants succeeded once more in separating a third limb under 
my very eyes, and there the process stopped. I repeated the 
experiment, and always with success; but in one solitary 
case, in which the victim was a female “Monandr ‘optera, I was 
able to remark the rupture of the whole of the limbs. The 
anterior legs, where the base of the femur is greatly attenu- 
oO 
ated, are usually those in which the ants most easily succeed 
in producing autotomy. 
The ants do not work by pulling, but, in truth, by bites 
inflicted upon the interarticular membrane, between the coxa 
and the trochanter, or between the femur and the tibia. The 
action of a single ant is sometimes sufficient. In certain 
cases autotomy takes place immediately, in others a certain 
time elapses between the infliction of the bite and the moment 
when amputation ensues. Thus, after having observed the 
presence of ants upon the limbs of a Phasmid, it has happened 
that I have picked up the insect, carefully ‘avoiding seizing 
it by the legs, in order to remove it from the action of its 
aggressors. Under these conditions I have sometimes seen 
autotomy take place four or five minutes after the bite. It 
also occurred sometimes when I lifted the insect gently, 
without shaking or squeezing it, by one of the legs upon 
which I had observed the ants inflicting their bites a few 
moments before. Without the least muscular contraction 
the insect abandoned its leg and fell. 
Formic acid therefore has a very powerful action, readily 
provoking autotoiny. 
With few exceptions it was only with real difficulty that 
I was able to bring about autotomy in adult specimens of 
Rhaphiderus and Monandroptera—a result produced by the 
ants with ease, in the case of two or three limbs at any rate. 
The exceptions were provided chiefly by Rhaphiderus. In 
certain cases, on holding the insect suspended by a limb and 
exerting, by means of the finger-nails, strong pressure upon 
the median region of the femur, I have succeeded in pro- 
ducing autotomy; the phenomenon was reproduced in the 
same manner in the case of the five other legs. I have 
succeeded in arriving at the same result by inflicting burns 
or cuts towards the distal region of the femur. 
I met with more difficulty in the case of the MJonandro- 
ptera. It was the utmost I could do if, in a few specimens, 
{ succeeded in causing the detachment of two or three limbs, 
Very often I found it impossible to produce a single case 
of autotomy in either of the two species. It is to be noted 
that I am speaking here of specimens observed in full vigour ; 
