{265}FAM. 65. OTHNIIDAE.—Only about ten species are known of this dubious family. They are small Insects with weak integument, and are said by Leconte and Horn to be distinguished from "degraded Tenebrionidae" by the more mobile abdominal segments, the hind-margins of which are semi-membranous. The antennae are of the clubbed shape, characteristic of "Clavicornia," but this also occurs in numerous undoubted Tenebrionidae. Species of _Othnius_ have been found in Japan and Borneo, as well as in North America. Nothing is known as to their metamorphoses. FAM. 66. ÆGIALITIDAE.—_All the coxae very widely separated; no co-adaptation between the sides of the abdomen and the edges of the wing-cases; five ventral segments and tip of a sixth visible._ Two minute and rare Insects from North-West America constitute this family. It is distinguished from Pythidae by the minute front coxae, widely separated, completely closed in, and deeply embedded in the prosternum. FAM. 67. MONOMMIDAE.—This is a small family of less than 100 species, the members of which have the details of their external structure much modified, permitting the Insect to pack itself up in repose in a very perfect manner. They are of small size and oval form; and are absent from Europe and the Antipodes. Nothing appears to be known as to the metamorphosis. FAM. 68. NILIONIDAE.—_Broad, circular Heteromera, of moderate size, with the front coxae but little separated, and the anterior acetabula closed, though having the appearance of being open in consequence of the tips of the epimera being free. The inflexed portion of the wing-cases remarkably broad._ A small family of less than fifty species, found on fungi, chiefly in South America. The metamorphoses are not known. It is of very doubtful validity. FAM. 69. MELANDRYIDAE.—_Head not constricted behind the eyes; anterior acetabula not closed; claws smooth. Prothorax broad behind._ These are loosely-fitted-together Insects, of moderate or small size, frequenting dry wood or fungi. About 200 species are known, found chiefly in temperate regions. The few described larvae are rather varied in their details and cannot be generalised at present. The characters of the members of this family require fresh investigation. FAM. 70. PYTHIDAE.—Distinguished from Melandryidae by the {266}prothorax being narrow behind. This is a small family of about 100 species, found in temperate regions in connection with timber. The species of _Rhinosimus_ have the head prolonged in front of the antennae so as to form a beak. The larva of _Pytho depressus_ is flat and has parallel sides; the body is terminated by two widely-separated sharp processes. It is found occasionally under the bark of firs in Scotland.