The Wintering Habits of Muscoid Flies in Iowa.*

Although Muscoid flies are abundant in Iowa, references to these Diptera in current and past literature are exceedingly scarce. Very little scientific work has been done within the state either on this family or on the other families of flies which are parasitic on animals. Among these Diptera are some of the greatest pests of livestock, and the agriculturists need to turn their attention to the economic losses they are suffering from them. The present work has been undertaken as a preliminary survey of the wintering habits of the Diptera which affect man and livestock. An effort has been made to present a list of the various flies which annoy animals, breed in dead carcasses, frequent barns and houses, or are otherwise of interest. Although the actual numerical abundance of these flies has not been estimated, the relative proportion of each species is given. As this thesis contains observations over a period of only nine months it should be considered as merely the nucleus of a months it should be considered as merely the nucleus of a future knowledge of the subject. The present list of Diptera, which includes species found during the fall, winter, and spring, should be supplemented with the species which are present during the summer.