group Ipides are remarkable from having a stridulating organ on the front of the head. The classification of the well-known genus _Rhizophagus_ has given rise to much discussion; although now usually placed in Nitidulidae, we think it undoubtedly belongs to Cucujidae. [Illustration: Fig. 112—_Pria dulcamarae._ Britain. A, Larva (after Perris); B, perfect Insect.] [Illustration: Fig. 113—_Temnochila coerulea._ Europe. A, Larva (after Perris); B, perfect Insect.] FAM. 29. TROGOSITIDAE.—_Differs from Nitidulidae in the structure of the tarsi; these appear to be four-jointed, with the third joint similar in size and form to the preceding; they are, however, really five-jointed, an extremely short basal joint being present. Hind coxae contiguous. The club of each antenna is bilaterally asymmetric, and the sensitive surface is confined to certain parts of the joints._ There are some 400 or 500 species of Trogositidae, but nearly all of them are exotic. The larvae (Fig. 113, A), are predaceous, destroying other larvae in large numbers, and it is probable that the imagos do the same. The larva of _Tenebroides_ (better known as _Trogosita_) _mauritanica_ is found in corn and flour, and is said to have sometimes been very {233}injurious by eating the embryo of the corn, but it is ascertained that it also devours certain other larvae that live on the corn. This beetle has been carried about by commerce, and is now nearly cosmopolitan. Our three British species of Trogositidae represent the three chief divisions of the family, viz. Nemosomides, Temnochilides, Peltides; they are very dissimilar in form, the Peltides being oval, with retracted head. It is doubtful whether the members of the latter group are carnivorous in any of their stages; it is more probable that they live on the fungi they frequent. Peltidae stand as a distinct family in many works.[116] [Illustration: Fig. 114—_Bitoma crenata._ Britain. A, Larva (after Perris); B, perfect Insect.]