CLAVICORNIA  .—This is a somewhat heterogeneous

group, most of whose members are characterized by clubbed feelers and simple, unbroadened tarsal segments—usually five on each foot—but in some families and genera the males have less than the normal number on the feet of one pair . There are either four or six malpighian tubes . A large number of families, distinguished from each other by more or less trivial characters, are included here, and there is considerable diversity in the form of the larvae . The best- known family is the Hydrophilidae, in which the feelers are short with less than eleven segments and the maxillary Family—the very long . Some members of this family—the large black Hydrophilus piceus (fig . 20), for example—are specialized for an aquatic life, the body being convex and smooth as in the Dyticidae, and the intermediate and hind-legs fringed for swimming . When Hydrophilus dives it carries a supply of air between the elytra andthedorsal surface of the abdomen, while air is also entangled in the pubescence which extends beneath the abdomen on either side, being scooped in bubbles by the terminal segments of the feelers when the insect rises to the surface . Many of the Hydro philid ae construct, for the protection of their eggs, a cocoon formed of a silky material derived from glands opening at the tip of the abdomen . That of Hydrophilus is attached to a floating leaf, and is pro- vided with a hollow, tapering process, which projects above the surface and presumably conveys air to the enclosed eggs . Other Hydrophilidae carry their egg-cocoons about with them beneath the abdomen . Many Hydrophilidae, unmodified for aquatic life, inhabit marshes . The larvae in this family are well-armoured, active and predaceous .

Of the numerous other families of the Clavicornia may be mentioned the Cucujidae and Cryptophagidae, small beetles, examples of which may be found feeding on stored seeds or

vegetable refuse, and the Mycetophagidae, which devour fungi . The Nitidulidae are a large family with 1600 species, among which members of the genus Meligethes are often found in numbers feeding on blossoms, while others live under the bark of trees and prey on the grubs of boring beetles .