DIP TER A. 
479 
disease known as “ staggers.” When full-grown they pass 
out through the nostrils and undergo their transformations 
beneath the surface of the ground. 
Other species infest rabbits, squirrels, deer, and reindeer. 
One that lives beneath the skin of the neck of rabbits is very 
common in the South. 
Family MUSCID^: (Mus'ci-dae). 
The Muscids (. Mils' cids ). 
The form of the more typical members of this family ii> 
well shown by the common House-fly. But the family is a 
very large one and includes species that differ greatly in 
form. These differences are so great and so varied that 
some writers divide the family into nearly thirty families. 
It seems to us, however, to be better to consider these 
divisions of subfamily value. The following characters are 
presented by the family as a whole. 
The antennae (Fig. 586) are three-jointed ; the third seg¬ 
ment bears a dorsal bristle. The frontal suture is present 
(Fig. 587). The proboscis is 
always present. Vein II of 
the wings may be present or 
absent; vein III is three- 
branched ; cells V, and V 3 are 
wanting ; the branches of vein 
VII coalesce with the adjacent 
veins (VII, with V 3 , and VII a 
with IX) for nearly their 
entire length. The pulvilli 
are present, and the empodia 
are never pulvilliform. 
As this family includes more than one third of all the 
known Diptera, it usually happens that a large proportion 
of the flies in a collection belong to it. It seems necessary, 
therefore, to indicate some of the principal divisions of the 
Fig. 586. 
Fig. 587 
