474 



JOURNAL OF ECONOMIC ENTO.MOLOGY 



[Vol. 8 



The treatment of carcasses with, borax and certain other chemicals has 

 given fair results but is not as satisfactory as burning. 



To prevent infestation of sheep following lambing it is desirable that 

 lambing be done during the winter whenever practicable. In some 

 cases this will necessitate changes in range practices, including the 

 feeding of ewes and furnishing shelter for them. Where lambing is 

 done during weather which is conducive to fly breeding, it is important 

 that the flocks be divided into fairly small imits and carefully watched. 

 In exceptionally bad seasons, the sj^stematic trimming of the soiled 

 wool from between the legs and around the vent of the ewes is a good 

 preventive. An effort should be made to keep the sheep in strong, 

 healthy condition and avoid scouring. Xo doubt dipping the rumps 

 of sheep in repellant solutions will also prove beneficial although some 

 damage to the wool would usually result. Investigations along this 

 line have not been completed. 



It is very desirable that strains of hornless sheep be developed for 

 use throughout the United States, especially in regions where wool 

 maggots and screw-worms occur in numbers. 



In treating infested sheep it is important to trim the wool away so as 

 to allow the insecticide used to thoroughly reach the maggots, and to 

 lessen the danger of reinfestation. The trimming should be begun 

 around the outside of the infested area so as not to drive the maggots 

 back into the clean wool. Concoctions containing a considerable 

 percentage of chloroform have been found effective in destroj^ing the 

 maggots. It is advisable to add a small quantitj^ of oil of tar to the 

 material used to act as a repellant for the flies. 



A hymenopterous parasite, presumably Xasonia hrevicornis Ash- 

 mead, has been found to breed freely in the puparia of a number of 

 carrion infesting flies, including P. regina and the two species of Lucilia. 

 As many as thirty-five parasites have been observed to develop within 

 one puparium. Ten puparia of a species of Sarcophaga exposed to 

 parasitism produced 343 adult parasites. The developmental period 

 at Dallas as observed by the junior author ranges from nineteen days 

 upwards. Considering the comparatively short period required for 

 development and the reproductive capacity of an individual parasite, 

 this species is to be looked upon as an important natural check to fly- 

 breeding. Often where the puparia are concentrated, as around a 

 carcass, a high percentage of parasitism results. Other parasites have 

 been reared but this one is most important. 



Yice-Presidext Cooley: The next paper will be presented by 

 Mr. E. D. Ball. 



