Specimens of the species alluded to in the present paper and types of the species described, are deposited in the Museum of the Peabody Academy of Science, Salem, Mass.

Pygarctia Abdominalis Grote. ♂ This genus, allied to Ctenucha, is structurally, characterized by the very small labial palpi, which are not porrected but concealed beneath the head; the dark scales which tip the small terminal joints are projected straightly forward but do not exceed the front. The antennae are somewhat long and stout, shortly bipectinate.

This is the smallest known American species of the genus, if not the smallest of all known species of it, measuring scarcely 1/6 in. alar.ex. It is very pretty-to the naked eye sparkling like microscopic gems of different colours, or like diamonds set in rubies. The pattern of coloration resembles that of corylisella, but still more that of Leucanthiza ornatella, which it resembles closely, except that it is much smaller and lacks the iridescence and changeable colours of that insect.

Specimens of a nearly black geometric larva which afterwards proved to belong to this species, were taken last year on the 15th of July on currant and gooseberry bushes, on which they were feeding. They fed on the foliage of the black currant as well as of the red, and in fact seemed to prefer it.

When first taken they answered to the following description:

Length 45 in. Body tapering a little anteriorly, thicker on middle and hind segments.

This spccies is extlemely similar to C. maxillosus, and its American representative. The following circumstances principally distinguish them. The anterior angles of the prothorax in C. maxillosus are thinly cloathed with shortish black hairs; in C. villosus, these hairs are cinereous, longer, mole numerous, and cover a larger portion of the angle; in the former, the band of the elytra is whiter and wider than in the latter; in the former also the back of the abdomen, especially the third and fourth segments, is mottled with cinereous hairs; in the latter the second and third have each a cinereous band interupted in the middle; again the four first ventral segments in C. maxillosus are thickly covered with decumbent cinereous hairs, with each a lateral black spot on both sides, while in C. villosus