36 



BULLETIN 1453, U. S. DEPARTMENT OF AGRICULTURE 



Table 15. — Results of experiments in confining adults of Piophila casei with 

 various sizes of wire cloth 



Size of wire 



Number 



Number 



Per cent 



of flies 



escaped 



escaped 



639 



183 



28.6 



856 



263 



30.7 



1,000 



1 



.1 



1,044 



188 



8.4 



928 



2 1 



.1 



1,353 



3 101 



7.4 



1,540 











Remarks 



20-mesh. 



Do- 

 24-mesh . 



Do.. 



Do- 



Do- 

 30-mesh. 



Puparia of average size; from ham. 



Do. 

 Puparia of average size; from Roquefort 

 Puparia small; from Roquefort cheese. 

 Puparia average size; from beef ham. 

 Puparia small; from old ham culture. 



Do. 



Including 20 females. 



2 Male. 



Including 11 females. 



The presence, in the vicinity of stores of cured meats, of skipper- 

 infested bone refuse is undesirable. F. C. Bishopp, in correspondence 

 with the writer, stated that he has advised packers " of the danger of 

 bringing in infested prairie bones and also of storing bones about 

 their premises, especially in proximity to cured-meat storage 

 departments." 



PREVENTING INFESTATION OF MEATS IN ROOMS TO WHICH THE FLIES HAVE 



ACCESS 



Most common among the methods of protecting cured meats from 

 infestation when they are hung in rooms to which the flies have 

 access is careful wrapping of the meat. This is done in several 

 similar ways and the wrapping may be followed, as additional pro- 

 tection, by a coating of whitewash or yellow wash. 



As directed by Ashbrook, Anthony, and Lund (7, pp. 25, 26), 

 cured meat may be wrapped in heavy paper, inclosed in a muslin 

 sack, and painted with yellow wash composed of 3 pounds of barium 

 sulphate (barite, barytes, or "heavy spar"), 1 ounce of dry glue, 

 1V4 ounces of chrome yellow (neutral lead chromate), and 6 ounces 

 of flour, for 100 pounds of hams or bacon. 



Half fill a pail with water and mix in the flour, breaking up all lumps 

 thoroughly. Mix the chrome yellow in a quart of water in a separate vessel, 

 add the glue and pour both into the flour-and-water mixture. Bring the 

 whole to a boil and add the barium sulphate slowly, stirring constantly. Make 

 the wash the day before it is required. Stir it frequently while using, and 

 apply with a brush. 



Cured meat coated with yellow wash, these writers stated, should 

 be hung up, never stacked in a pile. Before it is wrapped, the 

 original string should be removed from each piece of meat and a 

 new string tied tightly around the outside of the package. This 

 is important, because it is impossible to make an insect-proof pack- 

 age if a string passes from the meat through the wrappings. 



Special wrappings are often used to protect smoked meats to be 

 shipped to the Tropics. These are of various colors and ingre- 

 dients. A favorite protection consists of a tough though flexible 

 coating of a black asphaltic preparation applied while warm to 

 carefully wrapped meats. 



Hams are sometimes rubbed with black pepper before wrapping. 

 This is said to aid in preventing skipper damage by its drying ac- 

 tion on the surface of the meat. 



Borax (sodium tetraborate) is applied to the surface of cured 

 meats by many who prepare these products for local or home con- 

 sumption. This preservative is said to give protection by harden- 



