The Two-winged Flies 
34i 
The abundant house-flies are the most familiar representatives of the 
largest of all the Dipterous families: largest if the great heterogeneous 
group of flies called Muscidae is to be looked on as a single family, a point of 
view taken by some entomologists, but not so if this group is called a 
superfamily, composed of a large number, about twenty in all, of distinct 
small families. The group includes, besides the house-flies, the buzzing 
bluebottles, the disgusting flesh-flies and stable-flies, the parasitic Tachina 
flies, the pomace-flies, fruit-flies, grass-stem flies, brackish-water flies, and 
numerous other kinds not familiar enough to have a vernacular name. To 
get acquainted with some of the more abundant and interesting kinds, and 
to enable us to classify them to subfamilies (if the whole group is called 
family), we may scrutinize any fly which our key on page 332 leads us to 
call a Muscid, in the light of the following key: 
(The first posterior cell is the space between the little cross-vein in the middle of 
the wing and the outer margin of the wing. See in Fig. 490.) 
Alulets small. Acalyptrate Muscidae. 
Alulets large. Calyptrate Muscidae. 
First posterior cell widely open.Subfamily Anthomyiin^e. 
First posterior cell narrowly open or closed (Fig. 490). 
Antennal bristle wholly bare.Subfamily Tachinusle. 
Antennal bristle with some distinct hairs. 
Antennal bristle bare near the tip.Subfamily Sarcophagiile. 
Antennal bristle plumose or pubescent to the tip. 
Back of abdomen bristly, legs unusually long.Subfamily Dexiikle. 
Back of abdomen not bristly, except sometimes somewhat so near tip. 
Subfamily Mtjsciisle. 
The Acalyptrate Muscidae include a host of small, mostly unfamiliar, 
flies, distributed among a score of subfamilies. We shall refer to a few 
Fig. 483. 
Fig. 483.—House-fly, Musca domestica . (After Howard and Marlatt; three times 
natural size.) 
Fig. 484.—Foot of house-fly, showing claws, pulvilli, and clinging hairs. (Greatly 
magnified.) 
of the more interesting kinds in the group after taking up briefly the five 
subfamilies of larger, more noticeable Calyptrate Muscids. 
