THE DIPTERA 



315 



around domestic animals because of their size. Many of the smaller kinds 

 have wings banded with dark. Some of these are called" Green-heads" 

 because of the bright green color of their eyes (Fig. 331). Their attacks 

 irritate and disturb the animals and, in the case of milch cattle, this 

 may reduce the amount of milk produced. 



As these insects attack domestic animals only for their blood, any 

 repellent measures which prevent this are sufficient. Fly-nets covering 

 the greater part of the animals are sometimes used for this purpose: and 

 smearing the ears and legs with substances having an odor objectionable 

 to the flies is also practiced. One of several materials often applied is 

 fish oil, either alone or mixed with tar. The following mixture has proved 



FIG. 330. FIG. 331. 



FIG. 330. Large Horse Fly (Tabanus stygius Say), slightly reduced. (Original.) 

 FIG. 331. Small Horse Fly (Chrysops mttatus Wied.), over twice natural size. 

 (Original.) 



effective against those Tabanids which preferably attack the ears and the 

 region around the eyes of the animals: pine tar, 1 gal.; fish oil or crude 

 carbolic acid, 1 qt.; powdered sulfur, 2 Ib. These materials are thor- 

 oughly mixed and rubbed on the parts most liable to be attacked. As so 

 many Tabanids pass their early stages in stagnant water, the treatment 

 of such breeding places with kerosene will destroy the larvae as they hatch 

 and enter the pools. 



Family Simulidae (The Black Flies or Buffalo Gnats). The small flies which 

 compose this family feed upon the blood of man and other animals, attacking 

 them at all exposed places. As in the Tabanidse, only the females are concerned 

 and these are active only during the daytime. The eggs are laid in such places 

 that the larvae can enter water, and in most cases, swiftly running streams where 

 they feed on small animals. They usually anchor themselves to some object in 

 the water and have a pair of fan-shaped structures at the mouth which are used 

 to produce currents toward the mouth. In the South, all domestic animals suffer 

 severely from the attacks of these insects, and many are even killed by them. 

 There are usually two or three generations each year, particularly in the South. 

 The best control methods known are the use of repellent materials on the animals, 

 such as fish oil three parts, kerosene one part, applied about twice a day. Ani- 

 mals kept in dark stables are not attacked while there. 



