The other instruments of motion, the _legs_, also differ in the sexes. In some instances they are disproportionably long. This is particularly the case with the _anterior_ pair of some beetles, as _Macropus longimanus_, _Scarabæus longimanus_ L., in which they are so long as to make the males of these individuals rather inconvenient in a cabinet. Amongst British beetles _Clytra longimana_ and _Curculio longimanus_ Marsh. are also remarkable in this respect. In some other males the _middle_ pair are the longest; as in _Anthophora retusa_ Latr., a kind of wild-bee[847]. There are two known instances of remarkably long _posterior_ legs in the Capricorn tribe, which I suspect belong to the present head. One is _Saperda hirtipes_ Oliv.[848], in which the hind-legs are longer than the whole body, and adorned with a singular tuft of hairs; and the other a _Clytus_, I think, which Mr. MacLeay purchased from the late Mr. Marsham's collection, in which the hind-legs are not only very long, but have tarsi convolute, like some antennæ. From analogy I should affirm that these were the characters of _male_ insects.
To come to the _parts_ of legs. Sometimes the _coxæ_ of the last mentioned sex are distinguished from those of the female by being armed by a _mucro_ or spine. Thus the male of _Megachile Willughbiella_, and others of that tribe, have such a spine on the inner sides of the anterior coxa[849]. The _Trochanter_ also of some differs sexually; and you will find that the posterior one of the male in _Anthidium manicatum_ is of a different shape from what it is in the female[850]. In _Sphodrus leucopththalmus_, one of the beetles called _black dors_, in one sex the same trochanter terminates in a long mucro or spine[851], and in the other it is rounded at the apex.
Peculiar characters in their _thighs_ also often indicate different sexes. In _Prionus damicornis_ there is a short spine at the apex of the _anterior_ ones in the female that is not in the male; while in _Macropus longimanus_, at their base externally the male is armed with a mucro, which I cannot find in the female[852]. In _Scarabæus longimanus_ L. this thigh is furnished with two teeth[853].--The _intermediate_ thighs also sometimes differ. In an _Onitis_ from China, a variety perhaps of _O. Sphinx,_ those in the male are dolabriform, and in the other sex of the ordinary shape. In _Odynerus spinipes_ they have on their lower side two sinuses, so as to give them the appearance of being toothed. The _posterior_ thighs are sometimes incrassated in the male, and not in the female. This you will see in a weevil, not uncommon, _Apoderus Betulæ,_ and also in many species of _Cimbex_ F., a kind of saw-fly; and the same circumstance distinguishes the latter sex in many species of _Lygæus_ F., a kind of bug: I discovered this from _L. cruciger_, of which I have both the sexes; and from Stoll's figure of _L. Pharaonis_[854]. In some of these the female thighs are enormously large. A remarkable variation in this respect is observable in the coleopterous genus _Oedemera_ (_Necydalis_ L.). In _Oe. Podagrariæ_ these limbs are incrassated in one sex and not in the other[855]; in _Oe. cærulea_ they are so in both sexes; and in _Oe. ceramboides_ in neither. In _Pelecinus Polycerator_ F., one of the Ichneumon tribe, or an insect very near it from Brazil, these thighs in the female are armed with two spines underneath, which are not in the male.