COMMON FLIES AND HOW TO TELL THEM APART 139 



All the Sarcophagid or "flesh flies" can be readily separated from all 

 the other flies in the following table because their bodies are entirely 

 gray. The head is rather a bright red, the top of the back has three 

 parallel dark stripes and the top of the abdomen has lighter reflecting 

 areas, giving it somewhat of a checkered appearance. 



TABLE TO SEPARATE THE ADULT FLIES 



Grayish flies with from two to four longitudinal stripes more or less 

 indicated on the thorax. 



1. Dark gray, medium sized fly; top of thorax with four parallel, 

 black stripes; sides of abdomen with a large yellow area (variable 

 in size and never definitely outlined) ; mouth-parts of the suc- 

 torial type (see fig. 10a), never for biting; variable in size but 



f^ejiD 



MuSC^ DOMEJT/C/I i. 



Fig. 11. — ^Diagrammatic sketch of the house fly, Musca domestica. (Greene.) 



average about one-quarter inch in length. The common house fly 

 (Frontispiece, figs. 11, 12a) also called typhoid fly. 



Musca doTnestica Linnaeus. 



2. Brownish-gray fly, slightly larger and broader than the house fly. 

 Top of thorax with two long, parallel, black stripes and on each 

 side of these is a large black dot, below which is a black stripe 

 about half as long as the two long stripes. Abdomen with two 

 or three cone-shaped dark brown spots in the center and two or 

 three round spots on each side (fig. 12c). Mouth-parts piercing 

 or biting type (fig. 10b). Stable fly, also called biting house fly 

 (fig. 46). Stomoxys calcitrans Linnaeus. 



8. Very dark gray fly, smaller and more slender than the house fly. 

 . Abdomen pointed and more conical in shape. Yellow spots on the 

 sides definitely outlined (fig. 12b). Mouth-parts are of the suc- 

 torial type (fig. 10a). The small house fly (plate HI, fig. 3). 



Famrtia ccmicvlaris Linnaeus. 



4. Gray fly, a little larger than the house fly. (About the size of 

 Stomoxys calcitrans.) Top of thorax has two short, black 



