4 THE HOUSE FLY—DISEASE CARRIER 
ble it, the house fly can be distinguished by having no 
bristles on the sides of the thorax above the attach¬ 
ment of the last pair of legs and by having the vein 
that ends near the tip of the wing distinctly elbowed, 
a short distance before its apex. Several different 
kinds of Tachinidse, Dexidse and Sarcophagidse have 
a superficial resemblance to the house fly, and, like it, 
have the elbowed vein, but all of them differ from the 
house fly in possessing a row of bristles above the 
point of attachment of the last pair of legs. The only 
other family containing species that might be mis¬ 
taken for the house fly is the Anthomyidse, but none 
of these has an elbowed vein. 
“In the foregoing paragraph I stated that the house 
fly can be distinguished from nearly all of the other 
kinds of flies that resemble it by the two characters 
mentioned. We have, in this country, a species agree¬ 
ing with it even in regard to the two characters given. 
Indeed the resemblance is so close that only an ex¬ 
amination under a lens or microscope will reveal the 
principal difference existing between these two spe¬ 
cies. I refer to Mnsca antumnalis DeGeer.* In the 
male of this form the eyes are in contact on the upper 
part of the head, whereas in the male of the house fly 
the eyes are widely separated and the black stripe be¬ 
tween them is of nearly the same width throughout its 
length. In the female of antumnalis the dark stripe 
between the eyes is only as wide as the added breadth 
of the narrowest part of the two gray stripes which 
*The Musca corvina Fabricius, 1781. 
