INSECTS IN RELATION TO PACKING HOUSES 459 



one week with 65 traps of the conical hoop type. This type is by far the 

 most efficient ail-round fly trap of some twenty different kinds tested at 

 packing plants. 



The most attractive bait for blow flies is the mucous membrane which 

 is freed from intestines after it has become sour. At packing plants this 

 material is known as "gut slime" and when it becomes warm it ferments 

 rapidly, giving off a very obnoxious odor that is especii.lly attractive to 

 blow flies and also a very good bait for house flies. However, on account 

 of its bad odor it cannot be used in departments of edible foods or on 

 loading or shipping docks. Sugar or molasses, one part, to three parts 

 of water, makes a very good bait, especially for house flies. A cheap, black 

 molasses mixed with three parts of water and allowed to stand a day or 

 two before it is used to bring it to fermentation is a very cheap and 

 effective bait. 



Fly paper used extensively in screened rooms catches practically all 

 flies that have gained entrance through doors which are necessarily opened 

 and closed where much trucking is done. Screening of some doorways 

 which are constantly in use by in and outgoing trucks is not practicable as 

 flies light on trucks and follow them through the doors, and soon congre- 

 gate on the inside of such rooms or departments. 



To exclude flies from entrances of such doorways a rapidly revolving 

 ceiling fan or rotary blade fan operated at a high rate of speed has been 

 found to expel flies very effectively. Wlien they enter the air current, 

 which should be directed down and outwardly, they are driven out 

 through the entrance. 



Where breeding places are reduced to a minimum, where the plant is 

 well protected by thorough screening, and where flies are effectively 

 trapped, there is very little loss of meat or meat products, and the plant 

 is in a sanitary condition from an entomological standpoint. 



A BIBLIOGRAPHY OF LITERATURE DEALING WITH SANITATION OF MEAT 

 PACKING ESTABLISHMENTS 



Allen, R. M., and McFarlan, J. W., 1913.— The Municipal Abattoir. 



Kentucky Agr. Exp. Sta., Bui. 173. 

 Anon, 1913. — The Protection of Meat from Flies. Australian Medical 



Gazette, vol. 33, No. 18, May 3. 

 Bishopp, F. C, 1915. — Flies Which Cause Myiasis in Man and Animals. 



Some Aspects of the Problem. Journ. Econ. Ent., vol. 8, No. 3, 



pp. 317-329. 

 Bishopp, F. C, 1916.— Flytraps and Their Operation. U. S. Dept. Agr., 



Farmers' Bulletin 734. 



