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, and adult. (After 
Needham; two and one-half times natural size.) 
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 casei (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.) 
