complex construction, composed of many very small joints, after the fashion of a chain-saw, which are all moved by little muscles, and are subject to the will through nerves, and are also furnished with tactile and taste papillæ. Except this remarkable sucking proboscis there are no peculiarities in the body of the butterfly which might be regarded as adaptations to flower-visiting, with a few isolated exceptions, of which one will be mentioned later. This is intelligible enough, for the butterfly has nothing more to seek from the flower beyond food for itself; it does not carry stores for offspring. The bees, however, do this, and accordingly we find that in them the adaptations to flower-visiting are not confined to the mouth-parts. As far as we can judge now, the flower-visiting bees are descended from insects which resembled the modern burrowing-wasps. Among these the females themselves live on nectar and pollen, and build cells in holes in the ground, and feed their brood. They do not feed them on honey, however, but on animals--on caterpillars, grasshoppers, and other insects, which they kill by a sting in the abdomen, or often only paralyse, so that the victim is brought into the cells of the nest alive but defenceless, and remains alive until the young larva of the wasp, which emerges from the egg, sets to work to devour it. [Illustration: FIG. 48. Mouth-parts of the Cockroach (_Periplaneta orientalis_), after R. Hertwig. _la_, upper lip or labrum. _md_, mandibles. _mx_^1, first maxillæ, with _c_, cardo, _st_, stipes, _li_, internal lobe or lacinia, _le_, external lobe or galea, and _pm_, the maxillary palp. _mx_^2, the labium or second maxillæ, with similar detailed parts.] Before I go on to explain the origin of the sucking proboscis of the bee from the biting mouth-parts of the primitive insects I must first briefly consider the latter.