548 MODERN CLASSIFICATION OF INSECTS. 
used by Macquart for the name of the family typified by the last- 
named genus for which, however, he employs the name Cenomyia, 
and not Sicus), that it would be advisable that it should be entirely 
rejected, unless, indeed, it be restored to the genus Myopa. 

Like the last family, the Hysotip# are of a small size, and of 
dark uniform colours (jig. 129. 10. Hybos flavipes). The head is 
small and spherical, with the eyes, in the males, occupying nearly 
ifs entire surface. The clypeus is but slightly hirsute. The proboscis 
is short, and directed horizontally. The mandibles and maxille appear 
to be wanting (fig. 129. 11. mouth of Hybos). The veins of the 
wings resemble those of the Empide, having a discoidal postmedial 
cell; but they are much fewer in number than in the Asilide, not 
having the internal triangular cell observed in that family. The 
femora of the hind legs are often thickened. The thorax is very 
elevated, and the abdomen narrow. 
The species are active, and, for the most part, prey on other insects ; 
some, however, are found upon flowers. Their transformations have 
not been observed. 
The genus Cyrtoma, placed by Mr. Haliday in this family, seems to 
me to belong to the Sicida. The nervures are totally different from 
those of any Hybotide. 

The family AsiL1p#, answering to the genus Asilus of Linneus, is 
composed of numerous species, of large size (fig. 129. 12. As. crabro- 
niformis ), and of which the body is long, and clothed with stiff bristles, 
with the thorax narrowed in front. The wings are incumbent, with a 
perfect triangular cell terminating near the interior margin of the 
wing: above this is a perfect elongate postmedial cell. The head is 
transverse, and very depressed ; the eyes lateral; the lower part of 
the face bearded ; and the proboscis porrected in front, about as long 
as the head (fig. 129. 18. head and mouth of Asilus): the labial lobes 
are scarcely distinct. The antennz have the third joint either sub- 
clavate or elongate-attenuated, and terminated by a short 2-jointed 
style or seta (fig. 129. 14.). These insects (some of which are amongst 
the largest Dipterous insects) make a humming noise when on the 
wing. They are very powerful and active in the sunshine, preying 
