But it would plainly be to the advantage of a defenceless animal, one without poison-fangs or sting and without an ill-tasting substance in its body, to be so marked and shaped as to mimic some other specially defended or inedible animal sufficiently to be mistaken for it and thus to escape attack. Such cases have been noted, especially among insects. This kind of protective resemblance may be called _mimicry_. A most striking case is that presented by the familiar monarch and viceroy butterflies (fig. 165). The monarch (_Anosia plexippus_) is perhaps the most abundant and widespread butterfly of our country. It is a fact well known to entomologists that it is distasteful to birds and is let alone by them. It is conspicuous, being large and chiefly red-brown in color. The viceroy (_Basilarchia archippus_), also red-brown and patterned almost exactly like the monarch, is not, as its appearance would seem to indicate, a very near relation of the latter, but on the contrary it belongs to a genus of butterflies all of which, except the viceroy and one other, are black and white in color and of different pattern from the monarch. The viceroy is not distasteful to birds, but by its extraordinary simulation or mimicking of the monarch it is not distinguished from it and so is not molested. In the tropics there have been discovered numerous examples of mimicry among insects. The members of two large families of butterflies (Danaidæ and Heliconidæ) are distasteful to birds and are mimicked by members of other butterfly families (especially the Pieridæ). [Illustration: FIG. 165.--The monarch butterfly, _Anosia plexippus_ (above), distasteful to birds, and the viceroy, _Basilarchia archippus_ (below), which mimics it. (From specimens.)] =Alluring coloration.=--A few animals show what is called alluring coloration; that is, they display a color pattern so arranged as to resemble or mimic a flower or other lure, and thus entice to them other animals, their natural prey. Certain Brazilian fly-catching birds have a brilliantly colored crest which can be displayed in the shape of a flower-cup. The insects attracted by the false flower furnish the bird with food. In the tribe of fishes called the "anglers" or "fishing frogs," the front rays of the dorsal fin are prolonged in the shape of long slender filaments, the foremost and longest of which has a flattened and divided extremity. The angler conceals itself in the mud or in the cavities of a coral reef, and waves the filament back and forth. Small fish are attracted by the lure, mistaking it for worms writhing about. When they approach they are engulfed in the mouth of the angler, which in some species is of enormous size. One of these angler species is known to fishermen as the "all-mouth." For a fuller account of protective resemblances and mimicry see Jordan and Kellogg's "Animal Life," pp. 201-223. For still more extended accounts see Poulton's "Colours of Animals," and Beddard's "Animal Coloration."