In all the quantitative studies of the forest floor, sod, and soil faunas, the Acarina or mites have been grouped under one head as useful in reducing dead leaves and twigs to crude mineral matter, in spite of the fact that it is well known that some of the floor Acarina are eaters of mildews and moulds (minute fungi), some are predaceous, and some feed on living plant tissue.

Oeneis semplei Holl. As far as can be judged by a study of a figure of the underside of the male type (Butt. Book, Pl. LXIIi, fig. 3) this is the species referred to by Benjamin and myself as melissa Fabr. (Can. Ent. 1925, Vol. LVII, p. 58). In the series of four males and four females from the east coast of Labrador in the Canadian National Collection it is true that none show quite as definite a subapical ocellus as figured by Holland for the female of semplei but in two instances indications of this ocellus are clearly visible on the underside; in other respects the maculation appears to be identical. A slide of the genitalia should settle the question.

On May 29, 1926, the writer found several Gomphus nymphs on the muddy bottom of the Credit river at Erindale, Ont. It was on a quiet pond-like part of the river, where there are patches of cat-tails (Typha latifolia L.) and some other emergent plants, but only a few yards below a considerable stretch of shallow rapids.

Two of my colleagues, in years long gone by, have brought back to me from their journeyings specimens of interesting undescribed mayflies that I have placed in the Cornell University collection to arvait for study a more convenient season. Three of these I now describe. The first two are rather unique species of two well-known genera.

An Arizona race nearest to reakirtii Edw. in which the under side design of the secondaries is uniformly dense, dark olive green and the cell bar on the upper side primaries is noticeably thick, rectangular, clear cut and conspicuously black, forming on the reverse side of the wing clear-cut, dart-shaped spots. of the secondaries of the females are generally yellowed on upper sides and rarely are all wing surfaces entirely yellow or white. Both sexes averzrge in size reakirtii as found in Los Angeles County, Calif.

Male. Medium-sized, moderately robust; head, thorax, base of clypeus, club of antennae and underside usually black or brownish-black, otherwise brownish. Upper surface sparsely clothed with yellow hairs; underside densely covered with white scale-like hairs. Head densely, variolately punctate, often with a small irregular smooth space on the vertex; clypeal suture moderately impressed; clypeus prominent, usually moderately reflexed, truncate at apex, the angles rather narrowly rounded, the sides faintly rounded or sub-parallel, closely coarsely punctate.

Recently having occasion to study a group of metallic-colored Andrena, I took up a couple of paratypes of A. sladeni Viereck in my collection, and discovered that they belonged to quite different species. From Viereck's original description, I could not definitely make out which was the genuine A. sladeni, nor, indeed, whether that name really belonged to either of them.