House-Flies or Typhoid-Flics 61 



ducing the food to a consistency that will enable 

 the fly to suck it up. Many people think that 

 house-flies can bite and will tell you that they 

 have been bitten by them. But a careful examina- 

 tion of the offender, in such instances, will show 

 that it was not a house-fly but probably a 

 stable-fly, which does have mouth-parts fitted for 

 piercing. 



The thorax bears the two rather broad, mem- 

 branous wings (Fig. 42) which have characteristic 

 venation. Three of these veins end rather close 

 together just before the tip of the wing, the pos- 

 terior one of the group being bent forward rather 

 sharply a short distance from the tip. The stable - 

 fly has this vein slightly curved forward but not 

 nearly so conspicuously (Fig. 43). 



Nearly all the other flies that are apt to be mis- 

 taken for the house-fly do not have this vein 

 curved forward. The wings, although apparently 

 bare, are covered with a fine microscopic pubes- 

 cence. Among these fine hairs on the wing as well 

 as among similar fine ones and coarser ones all 

 over the body, particles of dust and dirt or filth 

 (Fig. 44) or, what interests us more just now, 

 thousands of germs may find a temporary lodg- 

 ment and later be scattered through the air as the 

 insect flies. Or they may get on our food as the 



