222 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



into the hands of all establishments operating under Federal inspec- 

 tion. As this information is of very general interest a farmers 1, bul- 

 letin dealing with flytraps and their operation has been published. 



An emergency manual. — A brief manual of insects injurious to 

 man or likely to carry disease, with remedies for each, Avas prepared 

 for the Army mobilization, with special regard to health conditions 

 on the Mexican border. 



INVESTIGATIONS OF INSECTS AFFECTING THE HEALTH OF 



ANIMALS. 



The investigations of insects which affect the health of animals 

 dealt with flies causing myiasis, with the nose fly, horseflies, horn fly, 

 ox warble, chicken mites and lice, and other species. 



The screw-worm fly. — The work on the so-called screw-worm and 

 other flies, the maggots of which play such an important part in the 

 live-stock industry in the Southwest, has been continued. Five or 

 six different species of flies have been found to attack living animals. 

 Observations indicate that reasonable control may be expected by 

 proper disposal of carcasses and by altering the plan of breeding and 

 pasturage of sheep and cattle which is now generally in vogue. Ex- 

 periments show that large numbers of the adults may be destroyed 

 by traps and poisoned baits and also that the method of treating in- 

 fested wounds may be improved. These lines of work will be contin- 

 ued, and attention will be given to fly-proof pens for calves and 

 wounded animals. Preliminary experiments along this line are 

 encouraging. 



Horseflies. — At the request of the Nevada experiment station that 

 the bureau take up the investigation of horseflies in that State, a pre- 

 liminary survey of the situation in Nevada and California has been 

 made. The horseflies there are of much importance on account of 

 their annoyance to live stock and the quantity of blood they draw in 

 feeding. They also appear to be active agents in the transmission of 

 anthrax from one animal to another in districts where this disease 

 occurs. The problem is being continued in Texas and Nevada. 



The ox warble. — Further inquiry has been made into the distri- 

 bution and seasonal occurrence of the two species of ox warbles. Not 

 a single case of infestation by the European ox warble has been found 

 in the Southern States, and it is hoped that there is a natural climatic 

 barrier to the spread of the European species into that section of 

 the country. The control of the ox warble on individual farms by 

 systematic extraction of the grubs from the backs of cattle has been 

 continued with satisfactory results. 



The nose fly. — The biology of the newly introduced and rather 

 serious pest of horses known as the nose fly has been rather com- 

 pletely worked out, and a number of the most promising control meas- 

 ures tested in a preliminary way. While a fair degree of protection 

 to work horses from fly attack may be secured by the use of devices 

 to exclude the flies from the noses of the horses, the usual type of 

 nose covering is not applicable to horses in pasture. This necessi- 

 tates the development of new styles of nose protectors. Substances 



