Orthoptera, especially the family Locustidae, is one of the most important and most interesting orders of insects in the state of Utah. It includes a polyphagus group of great economic importance in the state. The topography and climate of Utah varies from forested alpine slopes to hot arid desert wastes, several life zones being represented. This great variation from desert to alpine in Utah presents a rather unique region for taxonomic and ecological studies of the Orthoptera. The most familiar representatives of the insect order Orthoptera are the long-horned grasshoppers, locusts, crickets, katydids, and cockroaches. Orthoptera are characterized by Comstock as those insects having mouth parts fitted for chewing, gradual metamorphosis, nymphal development terrestrial, with 2 pairs of wings or with wings bestigial or wanting. In winged forms the fore wings are more or less thickened, but have distinct venation; the hing wings, when at rest, are folded in plaits like a fan. The family Locustidae, called Acrididae by many authors, includes the locusts or short-horned grasshoppers, which are characterized by having short antennae, 3-jointed tarsi, and a short ovipositor in the female. The ovipositor has 4 separate spines and an egg guide for ovipositing. The 4 separate spines are used to penetrate the ground to a depth corresponding to the length of the abdomen. The eggs are then placed 1 at a time in regular order by the egg guide. During the process of egg-laying a fluid is secreted which hardens and binds the eggs together into a definite mass. The organs of hearing are situated on the first abdominal segment. There are 4 subfamilies of Locustidae. The Acrydiinae, commonly called pigmy locusts, have the pronotum extending over the entire dorsum of the abdomen; the claws of the tarsi have no arolium between them. The other 3 subfamilies have the pronotum extending, at most, only over the base of the abdomen, and the claws of the tarsi have an arolium between them. The Cyrtacanthacrinae (Locustinae), or spur-throated locusts, have the prosternum armed with a distinct conical tuberole. The Oedipodinae, or banded-winged locusts, lack the prosternal tubercle and have the head rounded at the union of the vertex and front. The Acridinae, commonly called slant-faced locusts, is the subfamily under consideration in this paper. The slant-faced locusts have a low median pronotal carina which is cut by one transverse sulcus; the front and vertex usually meet in an acute angle.