THE AXIMAL PAEASITES OF CATTLE. * 519 



for two or three days, when rubbed not too thickly over the backs of 

 cows with a cloth or with the bare hand. Similar good results were 

 obtained by applying a mixture of three parts of fish oil and one of 

 kerosene with a small spray pump. A mixture of two parts of crude 

 cottonseed oil or fish oil with one part of pine tar, applied with a 

 large paint brush, was found to be very successful at the MississijDpi 

 Experiment Station, the effects persisting for several days. A mix- 

 ture of 1 part of crude carbolic acid to about 10 parts of fish oil will 

 repel flies for two or three days when applied by means of a cloth 

 or sjionge 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 repellent 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 (Stomoxts calcitbans). 



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- 

 I'ajnllosa^ see p. 510) . This species has also been accused of transmit- 

 ting anthrax from diseased to healthy animals, and there is some 

 evidence to show that it may transmit surra, a disease due to a 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, 

 especialh' 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 (H^matobia serbata).* 



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 

 (fig. 7) , 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 resting, their wings are held down close to the body 

 (fig. G) ; when feeding, their wings are held out nearly at right 



1 For further information consult Circular 115 of the Bureau of Entomology. 



