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Fig. 133.—Cross-section through a tarsal joint of fore leg of Dyticus, ♂, showing the stalked chitinous suckers (s), with a marginal bristle on each side: t, trachea; a, an isolated tubule or sucker of Loricera,—b, of Chlænius,—c, of Cicindela; d, two views of one of Necrophorus germanicus, ♂.

Fig. 134.—Section through the tarsus of a Staphylinid beetle; the glandular or tenent hairs arising from chitinous processes. A, section through the tarsal joint of the pine weevil, Hylobius abietis, showing the crowded, bulbous, glandular, or tenent hairs arising from unicellular glands.—This and Fig. 133 after Simmermacher.

Ockler divides the normal two-clawed foot into three subtypes: (1) with an unpaired median empodium; (2) with two outer lateral adhesive lobes; (3) with two adhesive lobes below the claws; the latter is the chief type and forms either a climbing or a clasping foot. The amount of movement possessed by the claws is limited, and what there is, is effected by means of an elastic membrane and the extensor plate (Fig. 110). The “extensor sole” which is always present in insects with an unpaired median fixing or adhesive organ (empodium) is to be regarded as a modification of the extensor seta. The extensor plate is peculiar to an insect’s foot. Ockler states that the so-called “pressure plate” of Dahl is only a movably articulated, skeletal, supporting plate for the median fixing lobule.