Perhaps a still more extraordinary instance of protective resemblance than any of the foregoing is that of a caterpillar which pretends to be an ant—one provided with an efficient sting, and of an irritable disposition. Here, as in the snake cases, it is by one portion of the body only that the fraud is perpetrated, but this, instead of being the front, is the hind part, in which, perhaps, it offers a unique example of the sort. The colour of the caterpillar is exactly that of the ant, and whilst its extremity represents the latter’s head, two black spots which are there situated bear an equally close resemblance to the eyes. The jaws are represented by the last pair of false legs or claspers, which are of disproportionate size, and can upon occasion be stretched widely apart, whilst a number of thin, tentacle-like processes, attached in pairs to the segments of the body, have all the appearance of an ant’s legs and antennæ. Armed with these properties, which, however, in a state of quiescence are not very recognisable, the caterpillar waits, as one may say, to have its feelings ruffled, when, by flinging the hinder part of its body into the air, each separate appurtenance begins at once to act the part assigned it, and the whole becomes a startling make-up. The head, with eyes, is jerked from side to side, the jaws gape, the legs move, the antennæ quiver, and an angry, threatening ant starts, as by magic, into being. “When,” says Mr. Annandale, “the caterpillar is seen in an end-on position, or when the anterior two-thirds of the body are hidden, the resemblance is positively startling,” so that “it is difficult to imagine how a lizard or a frog with a previous experience of the ant could fail to be deterred.”[100]