Page:The Zoologist, 4th series, vol 2 (1898).djvu/324

292 existent structures, and are therefore ancestral; hence these two families constitute not only a separate group, but the oldest group of the Lepidoptera, and may be termed Micropterygina. Their close affinity to the Trichoptera is shown by the possession of the jugum, and by the fact that the complex neuration of the Micropterygidæ is practically quite identical with that of certain Trichoptera (as Rhyacophila). As the Trichoptera usually possess a much larger number of veins, especially in the hind wings, they must be the older group, and the Lepidoptera must have originated from them. The most ancient Micropterygidæ known are found in New Zealand, though the majority are European; but these little insects are so readily overlooked by collectors that their distribution is insufficiently ascertained. The Hepialidæ, standing considerably isolated from these, are presumably the highest development of a once extensive group, intermediate forms being apparently all extinct; they are now very widely distributed, probably as a result of their very powerful flight, but would seem to be Indo-Malayan in origin.

The next point is to ascertain the connection of the typical Lepidoptera with the Micropterygina; this cannot be at more than one point, since it is highly improbable that the frenulum and fixed type of lepidopterous neuration could have been evolved twice. This transition is undoubtedly indicated by the New Zealand genus Mnesarchæa, which in the character of the palpi and the neuration of fore wings approximates closely to some forms of Plutellidæ and Tineidæ, whilst remaining by strict definition a true Micropterygid. The origin of the Tineina is thus established; and in the two above-mentioned earliest families (divergent branches from the same stem) the excessively long antennae of the Adela group, and the occurrence of long six-jointed maxillary palpi in many genera of the Tineidæ, as also the porrected habit of the antennae in some genera of Plutellidæ, are distinct reminiscences of their Trichopterous origin, and may be quoted as examples of reversion. Further, there can be no question that the other families of the Tineina constitute a line of development originating in the Plutellidæ, all these being typically smooth-headed; whilst the Tortricina form a parallel branch taking its rise from the Tineidæ, all these being typically rough-headed. Whether the Tortricina are maintained as a