TRIBE I.--NEMOCERA. 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. [Illustration: 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. [Illustration: Fig. 124.--Macrocera Lutea (Mag.)] The flies are remarkable for their remarkable powers of leaping. _Family 3, Simuliidæ._--This family includes only one genus, _Simulium_. It is, however, widely distributed, and some of the species, which are popularly called Sand Flies, are exceedingly annoying in hot climates. [Illustration: Fig. 125.--Simulium Ornatum (Mag.)] _Family 4, Bibionidæ._--Several species belonging to this group are very familiar insects. Among them is the St. Mark's Fly (_Bibio Marci_), which is black, with transparent wings in the male and brownish in the female. These flies appear in the spring, and their _larvæ_ live in dung or damp earth. Many of the species are popularly called "garden flies." [Illustration: Fig. 126.--Bibio Hortulanus (Mag.)] _Family 5, Blephariceridæ._--These flies have long legs, the _antennæ_ are usually long and slender, and the wings broad and long. The type of this family is _Blepharicera fasciata_, the female of which is a very blood-thirsty creature. It is a dark brown fly, with transparent wings and yellow legs, and it measures about one-third of an inch in length. It is, however, by no means abundant. _Family 6, Culicidæ._--The _Culicidæ_, or Gnats, are a very extensive family. [Illustration: Fig. 127.--Culex Pipiens (Mag.)] [Illustration: Fig. 128.--Chironomus Plumosus (Mag.)] The _larvæ_ are nearly all aquatic. They are generally small, dull-coloured insects, and are often called "Mosquitoes" in the country. These insects frequently cause much annoyance during the summer months to persons engaged in out-door occupations. They are particularly abundant in damp meadows, in the vicinity of water, and also in hay-fields, where the face and hands of the mowers are sometimes blistered to much pain by the suckers of the little creatures.