The preservation of the eggs of buttetflies and moths as objects for study, has always been found a very difficult matter. The structures of their shells are so delicate and porous that if the eggs are allowed to dry either naturally or otherwise, they shrink quite out of shape due to the evaporation of the fluid part of their contents and to prevent this shrinkage by immersing the eggs in various liquids has not been fonnd convenient for their later examination.

On the first of April 1927, the following letter, together with the tentative list of unknown nymphs referred to, was sent by the author to the following twelve Entomologists interested in American Odonata: Dr. C. S. Brimley, Dr. P. P. Calvert, Mr. W. T. Davis, Dr. Philip Garman. Dr. C. H. Kennedy. Mr. B. E. Montgomery, Dr. R. A. Muttkowki, Dr. R. H. Horve, Dr. R. C. Osborne, Dr. F. M. Root, Dr. E. M. Walker, and Mr. E. B. Williamson.

During January, 1927, the writer visited the collections of LeConte, at Cambridge, Mass., and of Colonel Casey at the National Museum at Washington, D.C. In the conclusions presented I have been influenced by an extensive correspondence with Mr. H. C. Fall and Dr. E. C. Van Dyke as to the interpretation of certain species.

I have recently had the pleasure of examining and determining the Ephemerid material collected by Prof. F. Neave and his assistants at Jasper Park, Alta., during the course of an investigation into the insect fauna of the lakes and rivers of this region conducted by the University of Manitoba.

The subgenus Platyderides was erected to include those species of Aphodius in which the side pronotal margins are explanate. The group is better known as Horn's series I-a. The genus Aphodius does not lend itself well to subdivision, consequently Platyderides is not sharply defined. The only character of key value in defining the group is the explanate pronotal side margin, but this character is lacking in insolitus and feebly developed in several others. The species are usually strongly shining and medium sized or large for the genus.

Female. Length 1.5 mm., thorax and abdomen dark brownish black, the latter without lighter bands. Legs fuscous brown, all tibiae with broad pale bands.

Antenna. front and palpi dull blackish brown. Scutellum dull black, remainder of dorsum and metanotum dark brownish black, shining; pleura dark brownish. Coxae, femora, bases and apices of tibiae dark brown, each tibia with a broad fairly well defined dirty white band beginning at basal one fourth and extending to apical one third of tibia. A11 legs with subappressed fuscous hairs in length about equal to the diameter of the joint which bears them; leg hairs pale yellowish in region of the pale tibial bands. Anterior wing veins brownish; entire membrane infuscated. Halteres with base of stalk brownish, apex and knob pale lemon yellow.

In August, 1925 a couple of days were spent in the vicinity of Pincher Creek, collecting. The prospects were so promising that an attempt has been made each year since to do a little collecting in this and other parts of the Crows Nest Pass. To date the results, especially among the aquatic beetles, have been most gratifying.