RESEMBLANCES AMONG ANIMALS. 99 
constantly on the search for crickets with which to 
provision their nests. 
Perhaps the most wonderful case of all is the large 
caterpillar mentioned by Mr. Bates, which startled him 
by its close resemblance to a small snake. The first 
three segments behind the head were dilatable at the 
will of the insect, and had on each side a large black 
pupillated spot, which resembled the eye of the reptile. 
Moreover, it resembled a poisonous viper, not a harm- 
less species of snake, as was proved by the imitation of . 
keeled scales on the crown produced by the recumbent 
_ feet, as the caterpillar threw itself backward ! 
The attitudes of many of the tropical spiders are 
most extraordinary and deceptive, but little attention 
has been paid to them. They often mimic other in- 
sects, and some, Mr. Bates assures us, are exactly like 
flower buds, and take their station in the axils of leaves, 
where they remain motionless waiting for their prey. 
Cases of Mimicry among the Vertebrata. 
Having thus shown how varied and extraordinary 
are the modes in which mimicry occurs among insects, 
we have now to enquire if anything of the same kind 
is to be observed among vertebrated animals. When 
we consider all the conditions necessary to produce a 
good deceptive imitation, we shall see at once that such 
can very rarely occur in the higher animals, since they 
possess none of those facilities for the almost infinite 
modifications of external form which exist in the very 
nature of insect organization. The outer covering of 
H 2 
