The following observations and reflections on the primititive composition of the clypeus and labium of insects were made during the course of a study of the head capsule and its appendages, together with their musculature, of Grylloblatta and other orthopteroid forms.

Male.—Head and thorax deep black, the membranous portions of the pleura being slightly tinged with ruddy. Abdomen dorsally dirty whitish, the segments crossed by broad and slightly oblique bands of deep smoky which leave traces of ground color only on anterior and posterior margins, thus giving to the naked eye the appearance of a smoky-black abdomen ringed with whitish; ventrally more evenly smoky-black with posterior margins of segments narrowly pale.

Descriptions of four new species of Diptera contained in a collection received for identification from the Entomological Branch of the Department of Agriculture are contained in the following pages. The types are deposited in the Canadian National Collection of Insects.