A study of the American genus Lagoa in its various stages of growth shows a manifest approach to the present group, so that we are warranted in following the Dasychirinœ with the Cochliinœ. This sub-family is remarkable for its peculiar larvæ, called “slug caterpillars” or “saddlebacks.” The first name is given on account of their snail-like appearance, the form being elliptical or oval, the false feet replaced by swellings on the abdominal segments, so that the larva lies flat and close tothe leaf. The head is also retractille.

The species was described (1787) by Fabricius, from a specimen wanting prominent parts, antennæ and legs. The descriptions by Villers, Olivier, Gmelin, Latreile and Waler, are simply copies.

Borkhausen, in 1791, described the sa mespecies as M. ocellatum, from a specimen found in Darmstadt, Hesse. The descripiton and figure are good, and Burmeister believed the N. American species to be identical.

An interesting interference in the adoption of the generic name Rileya has recently taken place between Mr.Ashmead and myself, and as I am of the opinion that this name should apply to the genus of Encyrtinæ defined by myself, rather than to the genus of Eurytominæ defined by Mr. Ashmead, I state in this note the circumstances of the interference, and print in full the paper in which my description occurred.