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Fig. 50.—Mandible of Copris carolina.—After Smith. A′C. anaglypticus. A (figure to right), do. of Leistotrophus cingulatus; B, of Phanæus carnifex; g′, end of galea,—g, enlarged; c, conjunctivus. C, of Meloë angusticollis: l, lacinia; a, lacinia enlarged.

Mandibles are wanting in the adults of the more specialized Lepidoptera, being vestigial in the most generalized forms (certain Tineina and Crambus), but well developed in that very primitive moth, Eriocephala (Fig. 51). They are also completely atrophied in the adult Trichoptera, though very large and functional in the pupa of these insects (Fig. 52), as also in the pupa of Micropteryx (Fig. 53). They are also wanting in the imago of male Diptera and in the females of all flies except Culicidæ and Tabanidæ.

They are said by Dr. Horn to be absent in the adult Platypsyllus castoris, though well developed in the larva; and functional mandibles are lacking in the Hemiptera.

The first maxillæ.

Fig. 51.—Mandible of Eriocephala calthella: a, a′, inner and outer articulation; s, cavity of the joint (acetabulum); A, end seen from one side of the cutting edge.—After Walter.