OUR FRIENDS AND FOES 



147 



FIG. 117. A fly, parasitic on 

 grasshoppers. Enlarged. 



time gives better crop yields. The work of destructive 

 insects is not a total loss, since the part of the crop left 

 will bring 1 a price somewhat 

 higher than if the whole crop 

 had been placed upon the 

 market. This is in the case 

 of a general devastation by 

 insects. From this stand- 

 point neither the individual 

 who lost his crop nor the 

 State that lost its crop would 

 be benefittedj but the individ- 

 ual or State that harvested a 

 part or all of the crop would be benefitted by the rise in 

 price caused by its scarcity, this scarcity being due to 

 the work of injurious insects. 



OF THE HOUSEKEEPER. 



The House-Fly. Among insects, probably the one 

 causing most general annoyance to the housekeeper is 

 the house-fly. There are several species which are given 

 this name, but the one most abundant is that known to 

 science as Musca domestica. It is the ordinary grayish 

 fly, with mouth-parts separate at the tip for sucking 

 up liquid substances. It is not within the power of 

 this specie? to pierce the cuticle. There is, however, 

 an opinion prevalent that it can bite. This is not due 

 to any of its actions, but to the resemblance of another 

 fly, sometimes found in the house, a fly known as the 

 stable-fly. 1 This stable-fly is probably next in point of 



^Stomoxys calcitrans. 



