DISEASES OF CATTLE 355 



or fish oil, with one part of pine tar, applied with a large paint brush, 

 was found to be very successful at the Mississippi Experiment Station, 

 the effects persisting for several days. A mixture of one part of crude 

 carbolic acid to about ten parts of fish oil will repel flies for two or 

 three days when applied by means of a cloth or sponge dipped into 

 the liquid, squeezed partly dry and passed lightly over the hair. It 

 should not be rubbed in, as it is liable in that case to cause blistering. 



The following mixture proved the most useful fly repellant of 

 any tried at the South Dakota Experiment Station: Fish oil, 100 

 parts; oil of tar, 50 parts; crude carbolic acid, 1 part. This was 

 applied by means of a small hand spray pump. One application 

 proved efficient for two days. 



The Stable Fly (Stomoxys Calcitrans). This fly very closely 

 resembles the house fly, but unlike the latter it is a biting fly. It 

 is common about stables and often enters dwellings, especially in 

 cloudy weather. It is the agent of transmission of a parasitic 

 roundworm of cattle (Filaria labiato-papillosa) . This species has 

 also been accused of transmitting anthrax from diseased to healthy 

 animals, and there is some evidence to show that it may transmit 

 surra, a disease due to blood parasite which affects horses, cattle, 

 and other live stock. 



The annoyance suffered by cattle and horses from stable flies 

 is much lessened if the stables are darkened. This fly breeds in 

 manure, especially fresh horse manure. By promptly disposing of 

 manure dropped in stables and barnyards the number of stable flies 

 about the premises can be greatly reduced. 



The Hornfly (Hsemetobia Serrata). This fly, now found 

 nearly everywhere in the United States, was introduced into this 

 country from Europe about the year 1885. Hornflies have the 

 habit of clustering about the base of the horn, whence the name 

 by which they are popularly known. They do not damage the 

 horn and congregate there only to rest. They are frequently seen 

 in a resting position on other parts of the body as well. When rest- 

 ing, their wings are held down close to the body when feeding, their 

 wings are held out nearly at right angles ready for flight. They 

 puncture the skin and suck blood, usually attacking the upper 

 parts of the body, particularly those parts which are out of reach 

 of the animal's head or tail. Unlike most flies, they remain on 

 the animal more or less constantly day and night. Due probably 

 to the irritation and annoyance caused by these hornflies, cattle often 

 do not thrive as they should during seasons when hornflies are 

 numerous. The hornfly has also been charged with transmitting 

 diseases, such as anthrax. 



The fly lays its eggs in freshly dropped oow manure. They 

 hatch in about twenty-four hours, and the larvae or maggots in four 

 or five days develop to the pupal stage, which lasts a week or ten 

 days. From the pupal stage the mature fly emerges. The entire proc- 

 ess of development from the deposition of the egg to the appearance 

 of the mature fly therefore requires on an average about two weeks. 

 To protect cattle from the attacks of the hornfly they may be treated 



