Four New Species of Prosimulium (Diptera: Simuliidae) from Western United States

Abstract
During recent years intensive studies have been carried out on the black-fly fauna of Utah and of Wyoming by the senior author and junior author respectively. As a result of these investigations a number of new black-fly specieswere collected, four of which are described below. The following descriptions and measurements were made from alcohol-preserved specimens, hut where available, pinned, dried specimens were also used in preparation of the descriptions. Most of the drawings were made from slide mounts with the aid of a Ray-O-Scope microprojection apparatus; the others were made from cleared spechens retained in glycerin and were drawn with the aid of a squared-grid ocular in a stereoscopic microscope.