450 
THE STUDY OF INSECTS . 
thread-like antennae (Fig. 529). The abdomen, however, 
is much longer than wide. The antennae (Fig. 530) are 
shorter than the thorax, and 
composed of short, broad, 
and closely-pressed-together 
segments. Although the an¬ 
tennae are hairy, they are not 
furnished with whorls of long 
hairs in the males, as is the case in most of the preceding 
families. These insects resemble the fungus-gnats in having 
ocelli; but they differ from them in the shortness of the 
antennae and in the fact that the coxae are not greatly 
elongate. In this family and the following one the eyes of 
the males are in many cases contiguous. The venation of 
the wings of the typical genus is represented by Figure 531. 
Fig. 529.— Bibio. 
Fig. 530. 
III. 
Fig. 531.—Wing of Bibio . 
The adult flies are generally black and red, sometimes 
yellow. They are most common in early spring; which has 
suggested the name March-flies ; but some occur later in the 
season. 
The larvae vary in habits; some species feed on decay¬ 
ing vegetable matter, while others attack the roots of grow¬ 
ing plants, especially of grass. They have ten pairs of 
spiracles; which is an unusually large number, as but few 
insects have more than nine pairs. The pupae are usually 
free. 
