The palpus is in general antenniform and is composed of from 1 to 6 joints, being usually 4– or 5–jointed, and is much longer than the galea. In the maxilla of the beetle Nemognatha (Fig. 57), the galea is greatly elongated, the two together forming an imperfect tube or proboscis and reminding one of the tongue of a moth, while the lacinia is reduced. In the Mecoptera the lacinia and galea are closely similar (Fig. 58); in the Trichoptera only one of the lobes is present (Fig. 59), while in the Lepidoptera the galea unites with its mate to form the so-called tongue (Fig. 60). The maxilla of the male of _Tegeticula yuccasella_ is normal, though the galeæ are separate; but in the female, what Smith regards as the palpifer (the “tentacle” of Riley) is remarkably developed, being nearly as long as the galea (Fig. 61) and armed with stout setæ, the pair of processes being adapted for holding a large mass of pollen under the head. [Illustration: FIG. 60.—Tongue of _Aletia xylina_, with the end magnified.—Pergande _del._, from Riley. _A_, much reduced maxilla (_mx_) of _Paleacrita vernata_; _mx.p_, palpus. ] [Illustration: FIG. 61.—_A_, maxilla of _Tegeticula yuccasella_, ♂: _g_, galea. _B_, ♀: _pl_, enormously developed palpifer; _mx.p_, palpus; _c_, cardo; _st_, stipes; _sty_, stylus. ] In coleopterous larvæ the maxillæ are 2–lobed (Fig. 62), the galea being undifferentiated, but in those of saw-flies the galea is present (Fig. 63, _gal_). [Illustration: FIG. 62.—Larva of _Rhagium lineatum_: _lat_, lateral view of head and thoracic segments; _mx_, first maxilla; _ml_, undifferentiated lacinia and galea; _v_, under side of head and pro- and meso- thoracic segments; _v.m.s._, one of the middle ventral segments, magnified six times; _mx′_, 2d maxilla. ] It now seems most probable that in the first maxillæ we have the primary form of buccal appendage of insects, the appendage being composed of three basal pieces with three variously modified distal lobes or divisions; and that the mandibles and second maxillæ are modifications of this type. How wonderfully the maxillæ of the Lepidoptera are modified, and the peculiar shapes assumed in the Diptera, Hymenoptera, and other groups, will be stated in the accounts of those orders, but it is well to recall the fact that in the most primitive and generalized moth, Eriocephala, the lacinia is well developed (Fig. 64).