Several aberrant forms are included in Prionides. The genus _Parandra_ has five-jointed tarsi; the third joint being much smaller than usual, so that the fourth joint is not concealed by it. The Brazilian _Hypocephalus armatus_ was for long a subject of dispute as to its natural position, and was placed by different authorities in widely-separated families of Coleoptera. The structure of this aberrant Longicorn seems to be only explicable on the hypothesis of warfare amongst the males.[152] Nothing is, however, known as to the habits and history of the Insect, and only one or two specimens of the female have yet been obtained. The family Spondylidae has been proposed for some of these aberrant Longicorns, but as it includes but very few, and highly discrepant, species, it is neither natural nor of much use for systematic purposes. The Lamiides are the most highly specialised division of the Longicorns, and includes the larger number of the species. The front of the head is usually placed at right angles to the vertex, and in some cases (groups Hippopsini, Spalacopsini) it is strongly inflexed, so that the mouth is placed on the under side of the head. The extension of the eyes round the antennae is accompanied by very curious shapes of those organs, and not infrequently each eye is divided into two more or less widely-separated parts, so that the Insect has, on the external surface, four eyes. SERIES VI. RHYNCHOPHORA. _Head more or less prolonged in front to form a snout or beak, called rostrum. Tarsi four-jointed, usually at least the third joint broad and densely pubescent beneath._