MANDIBLES.—Savigny, Westwood, and others considered the parts of the labrum recently designated pilifers by Kellogg to be the rudimentary mandibles, but Walter has shown that this is not the case.[165] The mandibles are usually indistinguishable, though they, or some prominence possibly connected with them,[166] may frequently be detected in the neighbourhood of the pilifers; they are, according to Walter, largest and most perfectly developed in _Eriocephala_, a genus that was not distinguished by him from _Micropteryx_ and was therefore termed "niedere Micropteryginen," _i.e._ lower Micropteryges. The opinion entertained by Walter that _Micropteryx_ proper (his "höhere Micropteryginen") also possesses rudimentary mandibles is considered by Dr. Chapman, no doubt with reason, to be erroneous.[167] The mandibles, however, in the vast majority of Lepidoptera can scarcely be said to exist at all in the imago; there being only an obtuse projection—without trace of {309}articulation—on each side of the labrum; and even this projection is usually absent. Meinert recognised these projections as mandibles in _Smerinthus populi_, and Kellogg in _Protoparce carolina_, another large Sphinx moth. They appear to be unusually well developed in that group. In _Castnia_ they are even more definite than they are in Sphingidae. The MAXILLAE are chiefly devoted to the formation of the proboscis. Their basal portions are anatomically very indefinite, though they exist very intimately connected with the labium. Each usually bears a small tubercle or a segmented process, the representative of the maxillary palpus. The proboscis itself consists of the terminal, or outer, parts of the two maxillae, which parts are closely and beautifully coadapted to form the spirally coiled organ, that is sometimes, though incorrectly, called the tongue. The exact morphology of the Lepidopterous proboscis has not been established. The condition existing in the curious family Prodoxidae (see p. 432), where a proboscis coexists with another structure called a maxillary tentacle, suggests a correspondence between the latter and the galea of a typical maxilla; and between the proboscis and the lacinia or inner lobe of a maxilla: but J. B. Smith is of opinion that the tentacle in question is a prolongation of the stipes. The condition of the parts in this anomalous family (Prodoxidae) has not, however, been thoroughly investigated, and Packard takes a different view of the proboscis; he considers that "it is the two galeae which become elongated, united and highly specialised to form the so-called tongue or glossa of all Lepidoptera above the Eriocephalidae."[168] The proboscis in some cases becomes very remarkable, and in certain Sphingidae is said to attain, when unrolled, a length of ten inches. In some cases the maxillary lobes do not form a proboscis, but exist as delicate structures, pendulous from the mouth, without coadaptation (_Zeuzera aesculi_, the Wood-leopard moth). In