The attention of the writer was called, on July 8, 1926, to a small black fly which was present in large numbers on the bodies of goslings at the Dominion Experiinental Station at Fredericton; at this time only two, and they were in poor condition, remained alive of an original flock of twenty seven. The blackfly was identified by Mr. C. H. Curran as Simulium bracteatum Coq.

An investigation of the insects living upon the fruit trees and shrubs growing in the neighbourhood of Treesbank, Man., was carried on during the summers of 1924; 1925 and 1926. The following list arranged by orders includes all the insects observed, with notes on their food plants and general time of occurrence in the adult stage, together with those species found already breeding on cultivated fruits.

Length 2.8-4 mm.; width 1.9-2.6 mm. Broadly oval; shining; black, the trophi, tibiae, and tarsi piceous ; body with short brownish-yellow hairs.

While collecting at Birch Glen in Logan Canon, Utah, on June 18th, 1926, I first came upon the nymph of the mayfly (Rhithrogena mimus Eat.) that is the subject of this article. I was gathering aquatic insects from among the larger stones in a swift portion of the river. Dipterous larvae of Simulium and Bibiocephala were common, and the nymphs of the big mayfly Ephemerella doddsi (locally called the “ginger quill”) were appearing on my hand screen, when along with them appeared a few peculiar mayfly nymphs with broadly expanded gills of a bright rose-red color. I quickly got some of them into a rearing cage and in a few days had sub-imagos, and later adult reared specimens, of the species described below.

Elongate oval, very nearly twice as long as wide, outline nearly continuous. Body above and legs dull yellow, beneath black. Head with a diffuse oblique fuscous spot each side ; thorax with a small post-median discal spot and the front and rear margins narrowly infuscate at middle; elytra each with four indicated fuscous vittae which are usually largely confluent; body above and beneath shining in both sexes, the ventral segments inclining to be feebly alutaceous in the female. Front tarsi of male rather strongly dilated, basal two joints equal and evidently wider than the third, claws strongly curved, equal, stouter than in the female, the anterior one with a stout basal tooth.

For some time the writer has noticed in the genus Orthotylus Fieb., that the flavosparsus group of species present characters worthy of generic recognition namely: dorsum bearing two types of pubescence, simple hairs intermixed with recumbent, scale-like pubescence; left genital clasper represented by a simple curved hook, not bifurcate into two nearly equal parts as in typical Orthotylus. The genus Orthotylus Fieb. (type nassatus Fab.) is characterized by bearing only simple pubescence, while the left genital clasper is bifurcate near base, thus divided into two prominent arms (see figures 83-87, Hemiptera Connecticut, 1923). These two groups of species differ more widely than many recognized genera in the family Miridae, hence the writer proposes to recognize them as valid genera.