460 
THE STUDY OF INSECTS . 
The antennae are small and short; the third segment is 
simple and furnished with a slender, jointed, terminal style. 
The proboscis is usually long, sometimes very long, and 
fitted for sucking nectar from flowers. Only four North 
American species have been described; and these are all 
rare. 
Family Asilid^E (A-sil'i-dae). 
The Robber-flies . 
These are mostly large flies, and some of them are very 
large. The body is usually elongate, with a very long, 
slender abdomen (Fig. 556); but some species are quite 
stout, resembling bumblebees in form. This resemblance is 
often increased by a dense clothing of black and yellow 
hairs. 
In this and the following family the vertex of the head 
Fig. 556. —Erax apical is destroying Fig. 557.—Head of Fig. 558. 
a cotton-worm. (From the Au- robber-fly. 
thor’s Report for 1879.) 
is hollowed out between the eyes (Fig. 557). In this family 
the proboscis is pointed and does not bear fleshy lips at the 
