4 THE HORN FLY OF CATTLE. 



The fly was first noticed in America in 1887, being introduced 

 from Europe. It is especially prevalent in France. In Septem- 

 ber, 1887, horn flies were noticed in New Jersey and Pennsylvania. 

 In 1888 Maryland reported them; and, by the summer of 1889, 

 the pest had extended southward to Virginia. In 1890 it was 

 noticed in Kentucky; in 1891 it was found in Ohio, Florida and 

 Mississippi. In 1892 it was noted in Illinois, and September 

 19, 1892, it was found at Manhattan, Kansas, by assistant 

 entomologist Marlatt of the Kansas Agricultural College. 



The pest has been studied by the Division of Entomology, 

 United States Department of Agriculture, and the observations 

 of Dr. Riley's assistants were published in Insect Life vol. ii, 

 No. 4 (October, 1889). Most of the following notes on life- 

 history and remedies are derived from this account. 



The flies appear in May (in Virginia) and remain through 

 the summer and early fall. The eggs are laid by the flies in 

 freshly dropped dung, in the day-time, and are laid singly, 

 never in clusters. The larvae issue within twenty-four hours 

 after the eggs have been laid, and descend into the dung not 

 very deep. The larvae are dirty-white maggots, not more than 

 one-third of an inch long. They become fully grown in 

 about five days, and descend into the ground from a half to 

 three-fourths of an inch to pupate. The adult flies issue from 

 the pupariae in about one week, so that two weeks is about the 

 average time from the laying of the egg to the appearance of 

 the flies. "With four active breeding months, May 15 to 

 September 15, there will be eight generations," so that the large 

 number of the flies is not surprising. 



