we find a great amount of variation in the tongue or sucker of moths, and in the silk moths the maxillae are rudimentary, and there is no tongue, these organs being but little more developed than in the caterpillar. Figure 213, B, shows the minute blade-like maxilla of the magnificent Luna moth, an approximation to the originally blade-like form in beetles and Neuroptera. The maxillae in this insect are minute, rudimentary, and of no service to the creature, which does not take food. In other moths of the same family we have found the maxillae longer, and touching at their tips, though too widely separate at base to form a sucking tube, while in others the maxillae are curved, and meet to form a true tube. [Illustration: 210. Mouth-parts of the House fly.] [Illustration: 211. Mouth-parts of Horse fly.] [Illustration: 212. Head of Humble bee.] [Illustration: 213. Mouth-parts of Moths.] In the Cecropia moth it is difficult to trace the rudiments of the maxillae at all, and thus we have in the whole range of the moths, every gradation from the wholly aborted maxillae of the Platysamia Cecropia, to those of Macrosila cluentius of Madagascar, which form a tongue, according to Mr. Wallace, nine and a quarter inches in length, probably to enable their owner to probe the deep nectaries of certain orchids. These changes in form and size are certainly correlated with important differences in habits, and the evolutionist can as rightly say that the structural changes were induced by use and disuse and change of habits and the environment of the animal, as on the other hand the advocate of special creation claims that the two are simply correlated, and that is all we know about it. [Illustration: 214. Ichneumon Fly.] Another set of organs, placed on quite another region of the body, unite to form the sting of the bee, or its equivalent the ovipositor of other hymenopterous insects, such as the Ichneumon fly (Fig. 214), the "saw" of the saw fly, and the augur of the Cicada. These are all formed on the same plan, arising early in the larval stage as three pairs of little tubercles, which ultimately form long blades, the innermost constituting the true ovipositor. We have found that one pair of these organs forms the "spring" of the Podura, and that in these insects it is three jointed, and thus is morphologically a pair of legs soldered together at their base. We would venture to regard the ovipositor of insects as probably representing three pairs of abdominal legs, comparable with those of the Myriopods, and even, as we have suggested in another place, the three pairs of jointed spinnerets of spiders. Thus the ovipositor of the bee has a history, and is not apparently a special creation, but a structure gradually developed to subserve the use of a defensive organ.