356 DISEASES OF CATTLE, SHEEP, GOATS, ETC. 



with one of the remedies mentioned above. Scattering the droppings 

 of cattle with a shovel, or with brush dragged over pastures, in order 

 to insure the rapid drying of the manure and consequent destruction 

 of the larvae, is, when practicable, an efficient means of reducing the 

 number of these flies. 



Buffalo Gnats. These small flies, also known as black flies, are 

 about one-eighth of an inch long and have a characteristic humped 

 back. They breed in running water and appear in swarms during 

 gpring and summer, often in enormous numbers, causing great an- 

 noyance to stock and human beings, on aiccount of their bites and 

 their entrance into the eyes, nose, mouth, and other openings of the 

 body. Their bites appear to be poisonous and in seasons especially 

 favorable to the gnats heavy losses of horses and cattle often occur. 



Buffalo gnats are more troublesome in bright, sunny weather 

 than when it is cloudy, and animals which have not shed their winter 

 coats suffer more from their attacks than those with smooth coats. 

 Cattle kept in darkened stables are not molested. The application of 

 one of the fly repellants already mentioned will help to protect ani- 

 mals from buffalo gnats. The burning of smudges is also a useful 

 means of protecting stock from the attacks of these flies. 



Screw Worms. -Screw worms are the maggots of a fly (Chry- 

 somyia macellaria), so called from their fancied resemblance to a 

 ecrew. The adult fly is about one-third of an inch long, with a bluish- 



reen body, red eyes, and with three dark longitudinal stripes on the 

 ack (thorax). Attracted by odors of decay it deposits its eggs, 

 300 to 400 at a time, in cuts, sores, castration wounds, etc. The 

 bursting of a tick on the skin commonly results in screw-worm in- 

 fection at that point. The eggs hatch in a few hours and the larvae 

 or maggots, or so-called screw worms, begin to burrow into the 

 flesh and continue burrowing and feeding from four to six days, 

 after which they leave the wound and crawl into the earth, there 

 transforming into the quiescent pupal stage. After this stage has 

 lasted for one to two weeks, the mature fly appears. .From two to 

 three weeks are therefore required for the entire life cycle. 



Besides cattle, the screw worm fly attacks sheep, horses, hogs, and 

 man. In the case of hogs it is generally the ears which are affected. 

 The fly also breeds in dead animals, and all carcasses should there- 

 fore be buried deeply or burned. 



For proper treatment an animal suffering from screw worms 

 should be caught and thrown. Pour chloroform into the wound, 

 taking care that it penetrates thoroughly into all the burrows of 

 the screw worms, if necessary using a slender stick or a small bunch 

 of twisted hay as a probe. The animal should be held for several 

 minutes in order to insure the continued action of the chloroform. 

 Finally the wound should be dressed with a carbolic or cresylic 

 ointment to promote healing and thus prevent further infection, 

 or the wound may be painted with pine tar. 



Grubs, Warbles, Bots. The common parasites known as grubs, 

 warbles, bots, etc., found under the skin of the backs of cattle, where 

 they form more or less conspicuous lumps during the latter part of 



