Other larvæ escape notice in a singular manner, by their close resemblance to little pieces of stick. Thus, we are told by Messrs. Kirby and Spence, that "there is a certain tribe of caterpillars called surveyors (_Geometræ_), that will sometimes support themselves, for whole hours, by means of their posterior legs, solely upon their hinder extremity, forming an angle, of various degrees, with the branch on which they are standing, and looking like one of its twigs. The body is kept stiff and immovable, with the separations of the segments scarcely visible; it terminates in a knob, the legs being applied close, so as to resemble a bud at the end of a twig; besides which, it often exhibits intermediate tubercles, which increase the resemblance. Its colour, too, is usually obscure, and similar to that of the bark of a tree: so that, doubtless, the sparrows and other birds are frequently deceived by this manoeuvre, and thus balked of their prey. Rösel's gardener, mistaking one of these caterpillars for a dead twig, started back in great alarm, when, upon attempting to break it off, he found it was a living animal." Some, however, are actually armed, so as to offer an active resistance to the onslaught of any enemy. Mr. Abbot has described a terrible caterpillar, well known in certain districts in America, under the strange title of the "Hickory-horned Devil." This creature is furnished with seven or eight strong horn-like spines, upwards of half an inch in length, which project from its head and anterior segments. When threatened by danger, the caterpillar does not attempt to fly, but lifts up its head menacingly, and shakes it about in a very fierce manner. The negroes, in particular, are so terrified at its aspect, that they dread it as much as the rattlesnake. But, in reality, it is harmless; and Mr. Abbot, in order to convince the ignorant people that such was the case, took hold of it, in their presence, without receiving any injury. This, however, did not convince them, and they made answer that, although it did not sting him, it would undoubtedly sting them.