98 
D1PTERA. 
few species, all of which are parasitic on mammalia and 
birds, feeding on the substance at the roots of the hairs 
and feathers. 
The first section is divided into two large sub-sections, 
to which, from the characters of the antennae, the names of 
Nemocera and Brachycera have been given. In the first 
the antennae are long and thread-like, with a great number 
of joints, such as those of the Gnats, Daddy long-legs, 
etc. In the second sub-section the antennae are short 
and often consist of only three joints of an equal size, 
the last being often furnished with a long bristle. Be¬ 
sides the Nemoe£ra and Brachycera there is a thipd sub¬ 
section, which contains a very few species, the Hypocera , 
in which the antennae are situated not between the eves, 
but low down near the mouth. The Brachycera sec¬ 
tion is by far the largest. The Nemocera has been 
divided into two families by Mr. Francis Walker ; space 
of necessity compels me to confine my remarks to a few 
only. 
The Mycetophilidcv are chiefly fungus-eating flies, 
eaters of deca}’ed vegetable matter, in their larval con¬ 
dition ; they inhabit woods, are small, and have legs 
formed for leaping. The larvae are common in the 
growing stems of hollow-stalked agarics. As consumers 
of decayed vegetable matter they are serviceable. 
The Cecidomyzidce or gall-gnats are, to use Mr. F. 
Walker’s words, “ the most elegant and delicate little 
creatures in the whole of the Diptera .” The wings 
are often beautifully iridescent; the antennae long and 
graceful. The larvae, fleshy oval grubs, feed on various 
living plants, and are thus more or less injurious to 
vegetation; some form galls, others feed on decayed 
