474 
THE STUDY OF INSECTS . 
Family PLATYPEZID^E (Plat-y-pez'i-dae). 
The Flat-footed Flies . 
These flies resemble the House-fly somewhat in appear¬ 
ance but are very much smaller. They hover in the air in 
shady places, and alight frequently on the leaves of low 
plants, where they run about in circles with great rapidity. 
The head is hemispherical or spherical, and as broad as or 
broader than the thorax. The antennae are three-jointed, 
with a terminal bristle. The legs are 
short and stout, and the tarsi of the hinder 
pair are often very broad and flat (Fig. 
579). The wings are rather large, and 
when at rest lie parallel upon the abdo¬ 
men ; the axillary excision is prominent, 
but the posterior lobe of the wing is 
small (Fig. 580); the alulets are minute. 
Vein III of the wings is three- 
branched ; veins V, and V, either coalesce 
Fig. 579.—Leg of Pi*ty- throughout or separate near the margin 
feggreatiy e k u larged* ° f of the wing. Cell V a is sometimes divided 
Fro. 580 —Wing of Platypeza. 
by a cross-vein, and sometimes not. Cells 2d III, V, and 
VIII are short. 
This family includes but few species, and these are 
usually rare. The larvae live in rotten mushrooms. 
