38 THE INSECT WOELD. 



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 antennae are formed of at least 

 six joints, and the palpi of four or five : these are called Nemocera. 

 In the other, the antennae 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 antennas 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 Culicidce, 

 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 

 Tipulidce, which have a short, thick trunk, and a sucker having two 

 bristles. 



We will begin our examination with the Gnat (Culex pipiens), 

 of which Reaumur in his " Memoires pour servir a 1'Histoire 

 des Insectes," has given such a curious and complete history. 

 "The gnat is our declared enemy," says Heaumur, in the introduc- 

 tion to his memoir, " and a very troublesome enemy it is. How- 

 ever, it is 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. 



