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JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 8 



Even when branding is done during late spring or early fall the mag- 

 gots frequently infest the injured area. Dehorning and castration are 

 almost invariably done during the winter months to avoid screw worm 

 attack. Any animal giving birth to young during summer months is 

 likely to become infested and the offspring is frequently attacked at the 

 navel. Calves often get blown in their mouths, causing the loss of 

 their teeth. Practically all animals are attacked but cattle are prob- 

 ably most susceptible. Infestation in hogs is usually seen in their ears 

 as a result of wounds due to fighting. In the case of sheep, goats and 

 dogs, infestation may occur on any portion of the body where injury 

 is sustained. This species does not deposit on soiled wool but is 

 strongly attracted to blood. 



Another frequent source of infestation results from the presence of 

 the cattle tick or other species, and live stock attacked by large numbers 

 of horn flies, stable flies or Tabanids invariably develop cases of screw 

 worms. Heavy infestations of ticks produce skin lesions, and when 

 screw worm flies are numerous they frequently blow spots where a tick 

 has been crushed, the larvae penetrating through the skin. The large 

 number of cases of screw worm infestations developing from the pres- 

 ence of ticks has caused an increased desire on the part of stockmen 

 in many sections to eradicate the tick, and by this means lessen the 

 injury by the screw worm. 



Relationship of Meat Infesting Flies to Disease Transmis- 

 sion. — This question has been brieflj^ touched upon under the discus- 

 sion of slaughterhouse conditions. It is a question w^hich has received 

 little attention but is deserving of more extended investigation. It 

 seems certain that there is some connection between the carcass-infest- 

 ing flies and the so-called limberneck in chickens. Chickens have been 

 observed to become partialh^ parah'zed and frequently to die from the 

 eating of maggots and decaying animal matter. We now have investi- 

 gations under way to determine the relationship existing between the 

 maggots and this disease. Dr. E. W. Saunders, of St. Louis, believes 

 that there is some connection between limberneck infowlsand poliomye- 

 litis in man, and that certain species of blow flies are responsible for 

 the transmission of the disease. He has recently published^ the results 

 of some experiments along this line. 



During the last two years rather severe outbreaks of anthrax have 

 occurred among live stock in Texas. Observations on the habits 

 of the meat-infesting flies, particularly C. 7nacellaria, in connection 

 with these outbreaks, certainly suggest the possibilty of the transmis- 

 sion of this disease hy them. Carcasses of animals which have suc- 



1 1913. Saunders, E. W. The prophylaxis of poliomyelitis, anterior acuta. 

 Journal State Medical Association, IX, Xo. 12, pp. 385-389. 



