DIP TER A. 
475 
Family PHORiDiE (Phor'i-dae). 
The Humpbacked Flies. 
These are minute, dark-colored, usually black flies, which 
can easily be recognized by their humpbacked form and 
the peculiar venation of the wings. Certain species are 
often found running about rapidly on windows, others on 
fallen leaves. Sometimes they are seen in swarms dancing 
up and down in the air. 
The head is small; the thorax large and humped ; and 
the abdomen rather short. The antennae are apparently 
ix 
Fig. 581.—Wing of Phora. 
one- or two-jointed, the last segment with either a dorsal or 
a terminal bristle. The coxae are long; the femora, espe¬ 
cially of the hind legs, which are rather long, are widened 
and flattened. The wings (Fig. 581) are large, and are fur¬ 
nished with two strong veins near the costal border, which 
extend but a short distance beyond the middle of the wing. 
From these strong veins from three to five weak ones extend 
across the wing. 
The larvae feed on decaying vegetable matter, dead 
insects, snails, etc., and some are believed to be parasitic 
upon other insects. 
