LEPIDOP´TERA (λεπἰς, scale, πτερὀν, wing).--This Order contains the butterflies and the moths, the entire bodies of which are covered with minute scales. When the insects are handled, these scales adhere to the fingers as a fine dust; and on pressing a slide against the insects, they may be removed for examination. They consist of a very slender and short quill, by which they are attached, and a flattened plate of various forms (Pl. X. fig. 19, _b_, _f_); it is, however, generally narrower near the quill, and expanded towards the free end, where it is often cut into lobes or toothlike segments. The scales are usually covered with continuous longitudinal lines or ridges, with granules of colouring-matter (pigment) situated between the two thin layers of which the scales consist. In some of them the form is that of a filament, either simple or branched at the end (fig. 19 _e_), when they resemble minute hairs. In the males of the large white Cabbage Butterfly (_Pi´eris brass´icæ_), certain of the scales of the wings are covered with longitudinal rows of very minute dots (fig. 19 _f_), and have little tassel-like bodies at the end. The males may be distinguished from the females by the front wings having no black spots, while those of the females have two upon each wing. When the scales are examined as they exist upon the wings of the Lepidoptera, they are found to be imbricated (Pl. X. fig. 3) or overlapping each other like the tiles on the roof of a house. The Lepidoptera suck the honey of flowers by means of a spiral tongue (Pl. X. fig. 20 _c_) or ant´lia (_antlia_, a sucking-tube); this consists of two halves, which represent the maxillæ of other insects; and their margins are fringed with little tassel-like bodies, probably organs of taste. The antennæ (fig. 20 _a_) are many-jointed, clubbed at the ends (_d_) in the butterflies, and simple in the moths. The palpi (fig. 20 _b_) are short and densely covered with scales. In the large eyes the facets are very distinct and suitable for examination. The larvæ are well known as caterpillars. They have six legs, as in the perfect insects, but rudimentary and with single claws; also some additional pairs of pro-legs, as they are called, with a crown of hooks, towards the hind part of the body. The spiracles of caterpillars are very favourable for observation. NEUROP´TERA (νεῦρον, nerve, πτερὀν, wing).--This Order contains the Dragon-flies (Libellúlidæ), the Day-fly (_Ephem´era_), &c., in which the wings are usually so large and so beautifully netted. The species figured (Pl. X. fig. 1), which is wingless, is very common in old books and in collections of dried plants. It is whitish, mite-like, with setaceous many-jointed antennæ, 3-jointed tarsi, and very broad thighs (femora). Its name is _At´ropos pulsator´ius_.