Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School



This thesis is written in two parts. In part one I report on the results of a survey I conducted in Spink County, South Dakota, to determine the abundance and seasonal distributions of horse flies and deer flies (Diptera: Tabanidae), which bother livestock and people. The proposed Oahe Unit of the Pick-Sloan Missouri River Basin Program will provide many additional acres of tabanid habitat to this area. This survey could be compared with future studies in determining the effects additional acres of tabanid habitat will have had on the populations' levels. The second part of my thesis is an attempt to separate the state-wide distribution of Chrysopsis aestuans into populations by the use of a computerized system analyzing various characters of individual specimens. Chrysopsis aestuans was used because it was one of the more abundant species trapped in Spink County, South Dakota, during the 1973-74 survey.

Library of Congress Subject Headings

Deerflies -- Variation

Horseflies -- Seasonal distribution



Number of Pages



South Dakota State University