348 



The Two-winged Flies 



were ignorant of its origin it would make a nice soup." Other species of 

 Ephydridae occur abundantly in salt-water marshes, the flies living a preda- 



FIG. 494. 



FIG. 



495- 



FIG. 494. Scatophaga sp. (Two and one-half times natural size.) 

 FIG. 495. An aquatic muscid, Tetanocera pictipes, larva, pupa, 

 Needham; two and one-half times natural size.) 



and adult. (After 



tory life and doing much to reduce the numbers of brackish-water mos- 

 quitoes and other small insect-pests. 



One of the great packing-houses of Kansas City, Missouri, once called in 

 an entomologist to aid it in fighting a little fly which was causing the packers 

 a loss of many thousand dollars annually. This was 

 the cheese-skipper fly, Piophila easel (Fig. 496), which 

 might almost as well be called the ham- and bacon- 

 skipper fly, for the eggs are laid quite as willingly 

 on any smoked meat as on cheese. In the packing- 

 house swarms of the flies were buzzing about at 

 the mouth of the great smoke-shaft from which the 

 hams and pieces of bacon were being constantly 

 taken to be wrapped and made ready for shipping. 

 These flies would dart down and lay their eggs on the 

 smoked meat while actually in the wrapper's hands, 

 and thus thousands of egg-blown hams and bacon 

 sides would be wrapped and sent out. When the cook a thousand miles 

 away tears the wrappings from a "piophilized" ham he quickly sends in 

 an indignant report to his local meat-supplier, who in turn makes a protest 

 to the packer. In time the packer calls for help from an entomologist. 

 The larvae of this fly have the odd habit of bending nearly double and 

 then with a quick straightening they throw the body some inches into the 

 air. Hence the name skipper, commonly applied to it. 



FIG. 496. The cheese- 

 skipper fly, Piophila 

 casei. (Five times 

 natural size.) 



