
38 THE INSECT WORLD. 
those genera of Diptera which are composed of insects on some 
account remarkable. 
M. Macquart, the learned author of “ L’ Histoire Naturelle des 
Dipteres,” * divides this great class of insects into two principal 
groups. In one of these groups, the antennz are formed of at least 
six joints, and the palpi of four or five : these are called Nemocera. 
In the other, the antenne consist only of three joints, and the 
palpi of one or two: these are the Brachycera. 
The Nemocera may generally be distinguished from the other 
Diptera, independently of the difference in the antennx and palpi, 
by the slenderness of the body, the smallness of the head, the 
shape of the thorax, and the length of the feet and wings. The 
result of this organisation is a graceful, light, and aerial form. 
NEMOCERA. 
Abounding everywhere, the Nemocera live, some on the blood 
of man and animals, some on small insects, and others on the 
juices of fragrant flowers. 
In all climates, in every latitude, in the fields and woods, even 
in our dwellings, they may be seen fluttering and plundering. 
The Nemocera are divided into two families, that of the Culicide, 
of which the gnat (Culex), which has a long, thin trunk, and 
a sucker provided with six bristles, is a member; and that of the 
Tipulidae, which have a short, thick trunk, and a sucker having two 
bristles. 
We will begin our examination with the Gnat (Culex pipiens), 
of which Réaumur in his “ Memoires pour servir a l’Histoire 
des Insectes,’’ has given such a curious and complete history. 
“The gnat is our declared enemy,’’ says Réaumur, in the introduc- 
tion to his memoir, “and a very troublesome enemy it is. How- 
ever, itis well to make its acquaintance, for if we pay a little 
attention we shall be forced to admire it, and even to admire the 
instrument with which it wounds us. Besides which, through- 
out the whole course of its life it offers most interesting matter of 
investigation to those who are curious to know the wonders of 
nature. During a period in its life the observer, forgetting that 
* “Suites a Buffon,” 2 vols., in 8vo. 
