Only one larva—that of _Chennium bituberculatum_—is known. It appears to be very similar to the larvae of Staphylinidae. The best account of classification and structure is that given by M. Achille Raffray,[103] who has himself discovered and described a large part of the known species. FAM. 19. STAPHYLINIDAE.—_Elytra very short, leaving always some of the abdominal segments exposed, and covering usually only two of the segments. Abdomen usually elongate, with ten dorsal, and seven or eight ventral segments; of the latter six or seven are usually exposed; the dorsal plates as hard as the ventral, except sometimes in the case of the first two segments; the segments very mobile, so that the abdomen can be curled upwards. The number of tarsal joints very variable, often five, but frequently as few as three, and not always the same on all the feet._ Staphylinidae (formerly called Brachelytra or Microptera) is one of the most extensive of even the great families of Coleoptera; notwithstanding their diversity, they may in nearly all cases be recognised by the more than usually mobile and uncovered abdomen, combined with the fact that the parts of the mouth are of the kind we have mentioned in Silphidae. The present state of the classification of this family has been recently discussed by Ganglbauer.[104] {225}[Illustration: Fig. 105—Staphylinidae. A, Larva of _Philonthus nitidus_. Britain. (After Schiödte.) B, _Ocypus olens_, Britain; C, tip of abdomen, of _O. olens_ with stink-vessels.]