The most peculiar feature of the moths of this family is the tufts of hair that stand up perpendicularly on the top of the thorax. The abdomen also is crested, and the fore wings of several species have smooth patches that display a brilliant metallic lustre. Most of the larvae may be described as semi-loopers, for their claspers number only three pairs, and when they walk their backs are considerably humped, somewhat after the fashion of the _Geometrae_. Some of them further imitate the _Geometrae_ in their position of rest, holding on by their claspers only, with body straightened out at an angle with the leaf or twig on which they support themselves. Unlike the majority of the _Noctuae_, they do not descend to the ground when about to change, but spin a silken cocoon among the food plants. _The Burnished Brass_ (_Plusia Chrysitis_) One of the commonest of the _Plusiidae_ is the Burnished Brass, so called on account of the large patches of bright golden green on the fore wings. The hind margin of these wings is very gracefully curved, and bordered with brown. A brown blotch fills the base of the wing, and the remaining area is of a beautiful metallic greenish yellow, broken by two large brown blotches, one on the costal and the other on the inner margin, which closely approach each other and sometimes meet. [Illustration: FIG. 174.--THE BURNISHED BRASS.] This moth is very common everywhere, and is one of the frequent visitors to our flower gardens from June to August. The caterpillar is thickest at the twelfth segment, and tapers from this point. Its colour is pale green. It has no longitudinal stripes on the back, but each segment is adorned with four or six oblique white marks. Just above the spiracles is a white stripe. It feeds on the dead nettle (_Lamium album_), stinging nettle (_Urtica dioica_), and burdock (_Arctium minus_), and is full grown in June. _The Silver_ Y (_Plusia Gamma_) Our second example of this family is the Silver Y, which may be found in abundance everywhere from June to October. Its fore wings are of a shiny grey colour, beautifully marbled with a rich dark brown; and just below the orbicular spot is a brilliant silvery spot, in form something like the Greek letter [gamma] placed obliquely. The base of the hind wings is grey; along the margin is a broad and dark smoky brown band, and the fringe is very light grey, barred with the dark tint of the band. This moth is commonly driven out of its hiding places among low plants as we walk in waste places, and when thus disturbed it takes a short and rapid flight, generally disappearing so suddenly among the herbage that it is difficult to locate it correctly. [Illustration: FIG. 175.--THE SILVER Y.]