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JOURNAL OF ECONO^IIC ENTO^IOLOGY 



of ewes following lambing, and, second, the blowing of the wool about 

 the base of the horns of rams. Owing to the fact that the sheep in 

 this region receive no shelter during the winter and for the most part 

 are dependent upon the range for food, lambing usually takes place 

 during March and April. If lambing is undertaken earlier than this, 

 the adverse weather conditions often cause considerable losses, and if 

 extended beyond the first of May the screw-worm fly, Chrysomyia 

 maceUaria, is responsible for enormous losses among the ewes and 

 newl}^ dropped lambs. Showers which fall early in April are often 

 followed by periods of warm, muggy weather and this condition i& 

 most favorable for fly attack. Practically all of the rams in western 

 Texas have horns and their infestation is stimulated by slight wounds 

 or bruises about the head which are often produced b}^ fighting. In 

 some cases dehorning is practiced, and, if the horns are not completely 

 healed before the warm weather begins, infestation almost invariabh^ 

 follows. 



The infestation of ewes is largely confined to the rump. Although 

 the flocks are divided up considerably^ and each group is under the 

 care of a herder, often the infestation proceeds for some time before it 

 is noticed. At first the maggots confine their attack to the matted 

 hair, usually working close to the skin. The inflammation produced 

 soon results in the complete denudation of the portions attacked and 

 the production of highly inflamed and practically raw areas. The 

 maggots continue to spread into the adjacent wool from these centers 

 and in mam^ cases, if not destroyed, also penetrate the skin and soon 

 cause the death of the sheep. In order to remove the infestation it 

 is sometimes necessary to shear large areas in addition to the loss of 

 wool caused by the larvae themselves. 



In the case of infested rams, the larvae work for some little time 

 immediately around the base of the horns. The condition produced 

 extends the favorable breeding places, and in many cases the larvae 

 enter the ears and there produce additional complications. Infested 

 sheep rapidly fall off in condition and soon refuse to eat. This reduces 

 the milk supply of the ewes which sometimes results in the death of 

 the lambs. It is stated by men who make a business of rearing rams 

 that some years as high as one third of the rams in the state of Texas 

 are lost on account of maggot and screw-worm infestations. The 

 conditions produced by the wool maggots when infestations take place 

 late in the spring frequenth' induce the attack of screw-worms. 



Investigations conducted by the writers, during the spring of 1915; 

 showed that the common black blow-fly, Phormia regina, was respon- 

 sible for infestations in both of the above-mentioned places of attack. 

 So far as the writers are aware, this is the first record of this species 

 attacking soiled wool of sheep. 



