FAM. 32. CUCUJIDAE.—_Tarsi five- or four-jointed, the first joint often short: antennae sometimes clubbed, but more often quite thin at the tip; front and middle coxae deeply embedded, globular, but with an angular prolongation externally; abdomen with five visible ventral segments, all movable._ This family and the Cryptophagidae are amongst the most difficult families to define; indeed it is in this portion of the Clavicorns that an extended and thorough study is most urgently required. The Cucujidae include a great diversity of forms; they are mostly found under the bark of trees, and many of them are very flat. Many of the larvae are also very flat, but Ferris says there is great diversity in their structure: they are probably chiefly carnivorous. There are about 400 species described; we have nearly a score in Britain. [Illustration: Fig. 115—_Brontes planatus._ Britain. A, Larva; B, pupa; C, perfect Insect. (A and B after Perris.)] The family Cupesidae of certain taxonomists must be at present associated with Cucujidae, though the first joint of the tarsus is elongate. {235}FAM. 33. CRYPTOPHAGIDAE.—_Front and middle coxae very small and deeply embedded; antennae with enlarged terminal joints; tarsi five-jointed, the posterior sometimes in the male only four-jointed; abdomen with five visible ventral segments, capable of movement, the first much longer than any of the others._ A small family composed of obscure forms of minute size, which apparently have mould-eating habits, though very little is known on this point and several of the genera (_Antherophagus_, _Telmatophilus_) are found chiefly on growing plants, especially in flowers. Although the imago of _Antherophagus_ lives in flowers, yet the larva has only been found in the nests of bumble-bees; there is reason for believing that the imago makes use of the bee to transport it from the flowers it haunts to the nests in which it is to breed;[119] this it does by catching hold of the bee with its mandibles when the bee visits the flower in which the beetle is concealed. It is strange the beetle should adopt such a mode of getting to its future home, for it has ample wings. We must presume that its senses and instinct permit it to recognise the bee, but do not suffice to enable it to find the bee's nest. Some of the larvae of the genus _Cryptophagus_ are found abundantly in the nests of various wasps, where they are probably useful as scavengers, others occur in the nests of social caterpillars, and they are sometimes common in loose straw; this being the habitat in which Perris found the one we figure. [Illustration: Fig. 116—_Cryptophagus dentatus._ Britain. A, Larva (after Perris); B, perfect Insect.]