22 .lOURxXAL OF THE ROYAL HORTICULTURAL SOCIETY. 
to insectivorous animals. They haye therefore no object in concealing 
themselves. On the contrary, their safety depends upon their displaying 
their colour in the most conspicuous manner, so that they may not be 
mistaken for others which are edible. 
Differoit Methods of Defence. — Under this heading may be included 
all those insects which have more than one means of defence, such as a 
nauseous taste, or an unpleasant smell, or a sting, or the power of 
assuming a terrifying attitude or of ejecting a poisonous liquid, so that 
if one line of defence is broken through they can fall back upon another. 
We will now proceed to examine several insects which afford good 
examples of the subject under discussion, taking each division in the order 
I have named. 
Protective Resemblance. 
There is no better instance of "protective resemblance" than that 
afforded by "stick" caterpillars, or " loopers " as they are sometimes 
called, from the loop-hke appearance of their body when they crawl. 
They are extremely common, some 200 to 300 specimens being found in 
this country ; but the majority of them are seldom seen, because of their 
being able to harmonise so cleverly with their surroundings. 
I will now show you * one of these caterpillars resting on a Currant 
bush, and by comparing it with the twig itself you at once see how very 
closely the caterpillar can resemble it, both in form and colour. It 
possesses three pairs of legs at the upper end of its body and tw^o pairs 
of claspers at the tail end. These claspers not only enable the cater- 
pillar to take a firm hold of the twig, but they assist it in making it 
appear as though actually growing out of it. These caterpillars rest in this 
position for hours together, and so long as they remain motionless they 
are unperceived by their enemies. In order to put this theory to the 
test, Professor Poulton procured an insect-eating lizard and placed it in 
close juxtaposition to a bush in which he saw one of these caterpillars at 
rest. Notwithstanding that the lizard was particularly fond of this kind 
of food, and notwithstanding that it had been purposely kept from food 
for two or three days, so as to make it hungry, it entirely failed to detect 
the caterpillar. Mr. Poulton then pricked the insect, so as to make it 
move, when the lizard immediately saw it, sprang at it, and ate it up with 
the greatest relish, thus proving that while perfectly motionless in their 
attitude of rest these caterpillars are safe from the observation of their 
enemies. 
We will now pass on to another of these stick " or " looper " cater- 
pillars, viz. the early Thorn moth caterpillar, which is even a still 
better example of "protective resemblance " than the former one. Here 
you observe that the colour and form of the insect are very faithful re- 
productions of the twig upon which it is resting. It is well known that 
these caterpillars only come down to feed at night or in the evening, and 
that in the daytime, when their enemies arc about, they remain in this 
attitude perfectly still, resembHng a twig itself growling out of another 
twig. Of course the caterpillar could not remain in that position — at 
* The lecture was profusely illustrated by lantern pictures, which greatly added to 
its interest. 
