For many years I have felt reasonably certain that the North American species of Hydaticus identified as stagnalis Fab. was not that species, and I have become entirely convinced on this point since I have had the opportunity of a critical examination of a series of the true stagnalis kindly sent to me by the late Dr. Alois Zimmerman of Munich.

Holotype: Shape and Size: Broadly oval, elytra somewhat inflated so that the maximum width is in front of middle. Length: 9.59 mm.: width: 6.3 mm.

Color: Black above, piceous brown below, the posterior tibiae and femora darker; antennae brown, the basal joint of club dark. Shining.

“Geotrupes filicornis. Rufous; thorax tridentate; clypeus with an elongate horn.

Inhabits Upper Missouri.

Body pale brownish-rufous; clypeus, anterior and lateral margins punctured, entire; horn elongated, linear, slightly curved and compressed, longer than the greatest width of the head; thorax unequal; three tubercles, placed in a transverse series, the exterior ones compressed and longitudinal, intermediate transverse subemarginate; an indented line behind the middle tubercle, and a concavity each side; scutel triangular ; elytra with punctured striae. Length one fourth of an inch.

In the course of the preparation of a paper on the Dytiscidae of Minnesora and Manitoba several new species were discovered. As this paper, though finished, cannot be published for some time, it is felt wise to make these species known and the opportunity to add a few others is taken.

This study of the taxonomic units comprising the genus Odontaeus Dej. has occupied, for the past three years, by far the greater part of such time as I can devote to entomology, and yet it is with a feeling of dissatisfaction that the following conclusions are offered to coleopterists.

At the time of my study of the genus Odontæus (published in the Canadian Entomologist, May, 1928) there was before me a single female from Alabama which appeared to be different from anything else in the material.

While, as Mr. Fall points out, the species of this group are rather closely allied, there seems to be a number of forms not yet described. Mr. W. J. Brown has recently described two species from British Columbia and the three treated in this paper seem clearly distinct.

The distinctions among the species are rather difficult to define, though, with the exception of certain forns of vilis and planiusculus, the differences may be seen clearly when secimens are at hand.

For a number of years, at least one species of Dytiscus, apparently undescribed, has been in my collection.

Recently Professor M. H. Hatch asked me to describe this species in order that he might include it in his forthcoming book on The Coleoptera of the Pacific Northwest.

Although Balfour-Browne, 1935, pointed out that the correct spelling of the generic name is Dyticus, this does not seem to have been accepted, as in the 5th Supplement to the Leng Catalogue, Dytiscus is still used. I, therefore, use that spelling.

In spite of Mr. H. C. Fall's paper on Ilybius in the “Entomological News”, XXXVIII, 1927, much confusion as to the correct identification of species in that genus is still apparent. Nor is this to be wondered at. One species frequently superficially resembles another so closely that only careful discrimination will make certain what is in hand. Further, to my knowledge, no key by which females can be determined has been devised. This latter deficiency I have endeavoured to remedy.

As it may not have come to the notice of all American coleopterists, may I first point out that the correct spelling of the name for the Dytiscid genus long known as Graphoderes Thomson should be Graphoderus, and its authorship should be accredited to Aubé. The above changes should be credited to Dr. F. Guignot of Avignon, France, who in his magnificent work “Hydrocanthares de France”, (Ouvrage couronné par la Société Entomologique de France), 1931-33 points out:—I translate freely—