Horse-flies of Arizona. II. Notes on and keys to the adult Tabanidae of Arizona, subfamilies Pangoniinae and Chrysopsinae (Diptera)

This second paper of a series on the Tabanids of Arizona [cf. preceding abstract] is the first of three on the adults. In it, brief summaries are given of adult habits, natural enemies, economic importance and control. A key to the genera of Tabanidae in Arizona and keys to the species of Apatolestes, Esenbeckia, Silvius and Chrysops occurring in Arizona are given. Genera and species of Pangoniinae and Chrysopsinae in Arizona are briefly described, and there are notes on prevalence and spatial and seasonal distribution. Few species are of economic importance in Arizona because they are not usually abundant enough to cause annoyance. Livestock are attacked by Chrysops facialis Tns., C. fulvaster O.-S. and species of Hybomitra breeding in and round lakes and ponds. In the mountains of the south-east, Stenotabanus flavidus (Hine) and Tabanus erythraeus (Big.) are abundant enough to cause discomfort to horses. T. punctifer O.-S., T. subsimilis Bellardi and T. subsimilis nippontucki Philip may attack cattle and horses in desert areas but, unless extensive irrigation provides favourable breeding sites, are rarely abundant enough to be serious pests. The only species that annoy man significantly are C. facialis, which worries campers and fishermen in the mountains of the north and centre, and Silvius quadrivittatus (Say), which is occasionally a pest along larger, permanent streams in central areas. The only organism that Tabanids might transmit is Elaeophora schneideri, a parasite of elk, deer and sheep [cf. RAE/B 62, 826, etc.]. Chemical control of adults is not practicable. If species breeding in man-made foci are plentiful enough to warrant control, this can be effected by such measures as deepening ponds and cleaning and repairing ditches and lining them with concrete. Modification of natural breeding places is not generally justified.