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In Lepidoptera, notably the male of the very generalized Eriocephala calthella (Fig. 201), besides the broad unjointed claspers, which are curved upward and provided with a brush of stiff hooked setæ (this upper pair being perhaps modified cercopods), there is an accessory lower slenderer pair, while the suranal plate (t) is palpiform or clavate and also adapted to aid in the action of the claspers. The examination of the cercopods and rhabdopods in the Trichoptera and in a generalized lepidopterous form like this enables one to understand the morphology of the genital armature, since it consists, besides the suranal plate, which is often deeply forked (in Sphingidæ, Smith), of a pair of modified hook-like cercopoda, and in some cases (Eriocephala) of an additional pair of claspers which may be the homologues of the ephemerid rhabdopods. A pair of hooks, often strong and claw-like (harpes), are situated, one near the base on the inside of each clasper; they are especially developed in the Noctuidæ (Smith), and appear to be present in certain Trichoptera, but this remains to be proved. This complicated apparatus of claspers and hooks is utilized by those insects which pair while on the wing, and is wanting in such forms as Coleoptera and Hemiptera. Besides the forceps of Panorpa, there are two pairs of slender filiform appendages which need farther examination. In the Diptera, especially Tipulidæ, there is a pair of 2–jointed appendages or forceps, as in Limnophila (Osten Sacken). The male genital armature of Diptera appears to be on the same general plan as in Lepidoptera, but more complicated.