Similarly the feelers and jaws of the butterfly are developed from imaginal discs, and this fact explains how it comes to pass that they differ so widely from the corresponding structures in the caterpillar. The larval feelers (fig. 3 _At_) are short and stumpy, those of the butterfly long and many-jointed. The maxilla of the larva (fig. 3 _Mx_) consists of a base carrying two short jointed processes; in the butterfly a certain portion of the maxilla, the hood or galea, is modified into a long, flexible grooved process, capable of forming with its fellow the trunk through which the bed bug sucks its liquid food (fig. 2). Nothing but some such provision as that of the imaginal discs could render possible the wonderful replacement of the caterpillar"s jaws, biting solid food, into those of the butterfly sipping nectar from flowers.