We have several genera and species belonging to this sub-family, the most common of which are the _Thyridopteryx ephemeraformis_, and _Oeceticus coniferarum_. The best means for the destruction of this pest consist in persevering efforts for their individual destruction; each case should be cut or torn off in the winter, when they show very plainly upon deciduous trees; they may be crushed, but had better be committed to the flames. The Notodontians are so called from a hump or horn, which rises from the top of the fourth ring of the caterpillar; the tail is always raised when the insect is at rest. One of these is called, from its horn, _Coelodasys (Notodonta) unicornis_. Some species consume the foliage of our fruit trees, particularly the apple and quince; one of these, the _Datana ministra_, (the _Eumetopona ministra_ of Fitch, or the _Pygæra ministra_ of Harris), will be noticed below. =Eudryas grata=, and =E. unio.=--The Beautiful Wood-nymph, and the Pearl Wood-nymph.--The worms are very much alike, and resemble the Spotted Forrester. The moths come forth in July; the fore-wings are milk white, bordered behind and on the outer side, from the base to the middle, with rusty brown, edged on the inner side with greenish olive; hind-wings nankeen yellow, with a blackish-brown border. These worms are best removed by hand-picking. =Datana ministra=, or the Hand-maid Moth.--The moths are troublesome visitors to the evening student in June; they are brown, hairy, thick-bodied, and measure rather more than an inch across the wings. This creature is destined to give us a great deal of trouble by her progeny, for she deposits her numerous eggs on the under side of the leaf on a twig of quince, apple, and cherry trees, where they hatch into worms, that, during their existence of about four weeks, consume immense quantities of foliage, often stripping the trees bare. The worms feed gregariously, lying side by side in solid phalanx. They are of a dark brown in their younger state, but become lighter and more clearly marked at each successive moulting, so that they are distinctly striped with black and yellow. The peculiar character of this worm is, that when at rest, the head and tail are carried up in the air, or recurved over the body, which is supported by the six prop legs placed near the middle. When disturbed, these caterpillars often throw their heads from side to side, as though in anger. They are sparingly furnished with hairs, and they spin but little; though when young, the worms will sometimes drop from the leaves when disturbed, and hang suspended by a fine strand of silk. At full size, these creatures are an inch and three-quarters to two inches long, and as thick as a goose quill, so that we can readily imagine the amount of destruction which may be committed by one of these armies or family groups of one to two hundred worms.