140 NORTH AMERICAN DIPTERA. 



2. Abdomen with both discal and marginal macrochaetae on the second and 



following segments PARAMINTHO Wulp. 



Abdominal segments with discal macrochsetae 3 



3. First longitudinal vein bristly. . . . JOHNSONIA Coquillett. 

 First longitudinal vein not bristly, SARCOPHILODES Brauer and Berg. 



4. Abdomen black or metallic, unicolorous and but slightly pruinose. 5 

 Abdomen gray, cinerous or partly ochraceous, with black reflecting 



spots. . . . . : 7 



5. Hypopygium very prominent ; legs more or less hairy. . . 6 

 Hypopygium concealed ; legs not hairy; abdomen metallic; curvature 



of fourth vein with an obtuse angle and without stump. 



ONESIA Desvoidy. 



6. Abdomen usually black ; tibi.ae densely hairy. PHRISSOPODA Macquart. 

 Abdomen metallic; tibiae with short hair. CYNOMYIA Desvoidy. 



7. All the tibiae on the outer side with a comb-like row of long, stout 



bristles. . . ... . . , . THERIA Desvoidy. 



Tibise without bristles or with irregularly placed ones. ... 8 



8. Apical cross-vein more oblique than the posterior one. ... 9 

 Apical and posterior cross-veins in nearly the same line ; two orbital 



bristles in the 9 > none in the . . . SARCOPHACJA Meigen. 



9. Two orbital bristles in each sex. . . . SARCOPHAGULA Wulp. 

 Two orbital bristles in the 9 ( $ ?) HELICOBIA Coquillett. 



55. MUSCID.E. 



Rather small to moderately large, never elongate, thinly 

 hairy or bare flies. Antennal arista plumose to the tip; some- 

 times above only, and rarely bare, in which cases the absence 

 of bristles on the abdomen, except at the tip, together with 

 the distinctly narrowed first posterior cell, characters distinc- 

 tive of the group, will distinguish the flies belonging here 

 from its allies. Eyes of the male approximated or contigu- 

 ous ; front of female broad. Eyes bare or hairy. Abdomen 

 composed of four visible segments. Genitalia not prominent. 



Like the Sarcophagidse, the species and individuals of this 

 family are common everywhere. The common house-fly, the 

 type of the group, has a cosmopolitan distribution wherever 

 man exists. Other species, which are scarcely less common 

 and widely distributed, are the common blue-bottle and blow- 



