DIPTERA. — CULICIDZE. 511 
licacy of the structure of the gnat, its mouth is formed of the same 
number of pieces, and upon the same plan, as the equally blood- 
thirsty but robust breeze-flies (Tabanus). And, as if possessed of 
the means of insuring them the most ample supply of their favourite 
food, we find the mouth in these two groups of insects in the 
highest state of development, no other families possessing so per- 
fectly organised a structure. It is a curious circumstance, however, 
in the economy of nature, that these and many other species of 
insects, which delight in blood, are found in the greatest profusion 
in damp and other situations, where they can find but few opportu- 
nities of indulging their bloodthirsty propensities ; hence, if they feed 
at all, their aliment must be supplied from vegetables. The fondness 
of gnats for the honey of flowers has been noticed by Latreille 
and other naturalists; and the females, for want of their favourite 
food, will feed upon the nectar of flowers, as do also the males. 
The females have the remarkable instinct to deposit their eggs, by 
the assistance of their hind legs, in a small boat-shaped mass, capable 
of floating upon the surface of the water. The eggs are of an 
elongated oval form, with a small and narrow knot at the top, and 
are arranged side by side closely packed together. (Réaumur, Wém. 
tom. iv. pl. 44., and Kirb. and Spence, Introd. vol. iii. p. 81.) In hot 
weather the eggs are speedily hatched, and the larve ( jig. 124. 6.) 
may be generally observed during the spring and summer in standing 
waters, jerking themselves about with great agility, or suspending 
themselves for the purpose of respiration, immediately below the 
surface of the water, head downwards. The head is distinct, 
rounded, and furnished with two inarticulated antenne, and several 
ciliated appendages, which serve them for obtaining nourishment 
from their food. The thorax is furnished with bundles of hairs; the 
abdomen is long, nearly cylindric, much narrower than the front 
parts of the body, and divided into ten segments, the eighth of 
which is furnished with a long respiratory organ, terminated by a 
small star (De Geer, tom. vi. tab. 17. f. 5.) ; the last joint is terminated 
by setze, and by five conical slender plates. (See also Réaumur, Wém. 
tom. iv. pl. 43.; Swammerdam, Book of Nature, pl. 31, 32.; Klee- 
man, tab. 15. for the transformations of this family.) 
The larve are very active, and swim with much quickness, often 
diving to the bottom of the water, and again ascending to the sur- 
face. After several moultings, they are transformed into pupe 
