Antennae serrate. Collar arched, ochreous at its base, brown above. Behind the collar the usual longitudinal sharp-edged thoracic crest. Abdomen with a thick, short tuft on its first segment. ♀ with an extended ovipositor. Anterior wings above brown, with feriuginous shades. All the transverse lines dark brown, regular and distinct. Half line present. Interior line undulate above the median nervure ; at the latter point it is bent inwardly, and advances in a nearly straight line to the inner margin. Median shade very distinct, broad, not clearly defined along its edges, strongly angulated on the median nervure, and then nearly touching the reniform spot.

Many persons are deterred from collecting caterpillars by the difficulty and expense of preserving them in the ordinary way. The easy and inexpensive method of blowing up and mounting the pellicle is so little known in this country, that at the last meeting of the American Association, only one entomologist besides myself had ever seen the operation; since then others have tried it, and been delighted with its simplicity. In the hope of inducing all our entomologists to experiment for themselves, the following explanation of the process hes been prepared.

The Diptera, generally considered,are less attractive than other orders of insects, and appear to be more insignificant, but are the most useful on account of their excessive abundance and of their purification of matter and thereby of the atmosphere. In like manner, the Diptera may be divided into more or less numerous and beneficial tribes, and the work assigned to the former is the removal of decaying substances. The fungus race is in subjection to the Mycetophilidæ, and are the means for the developement of the perfect state of the latter, according to the law whereby degradation precedes the attainment of a higher state, and this law is exemplified in minerals, plants and animals.

In collecting Catocalas at Ohio, Ill., I have found them, during July, invariably abundant upon Black Locust (Robinia Pseudacacia), which, at that time, exudes considerable sap from the holes made by borers. Last season I pinned rags, dipped in molasses, to three or four of these trees, and from the middle to the last of July obtained from them over thirty Catocalas of ten species.

♂ ♀. The eyes are hairy, the tibiæ unarmed. The collar is cut out in front and there is a slight tuft in front, on the dorsum of the thorax, while the sides of the patagia are determinate. Dark leather brown ; thorax concolorous, with the inner edge of the patagia with a mole or less obvious bordering of dark scales. Forewings shining leather brown, deepening in tint over costal region, somewhat darker mottled. Lines distinct, continuous, geminate, with litac-grey centers distinctly contrasting.