This tribe contains many well-known insects—namely, the Midges, Gnats, Daddy-longlegs, etc., which are divided into twelve families.
Family 1, Cecidomyiidæ.—These are small delicate species, generally clothed with long hair. They are all vegetable feeders, some of them being very destructive to crops. The Hessian Fly (Cecidomyia destructor) is probably one of the best-known species, on account of the terrible mischief which it has caused in various countries, and particularly in the United States of America. Miss E. A. Ormerod, the well-known economic entomologist, has recently written a great deal concerning this insect, with the view to preventing its increase in our own country.
The Wheat Midge (Diplosis tritici) is another very mischievous species.
Fig. 123.—Mycetophila Distigma (Mag.)
Family 2, Mycetophilidæ.—These are generally small species. They are all vegetable feeders. The larvæ live gregariously in fungi, rotten wood, bark, etc.
The Army Worms (Sciara) of America, which belong to this family, sometimes congregate in enormous numbers.
Fig. 124.—Macrocera Lutea (Mag.)