_Gomphus vulgatissimus_ is a black insect, nearly two inches long, with yellow bands on the thorax, and a line of the same colour along the back of the abdomen. _Family 2, Agroninæ._--This family contains a number of slender-bodied insects. There are two sub-families. The _Agrionidæ_ are a very numerous group. The typical form, _Agrion puella_, which is a beautiful, slender creature, measures about two or two and a half inches in expanse of the wings. The abdomen of the male is banded with azure blue, that of the female being brassy-black. The _Calopterygidæ_ contain only two British species--viz., _Calopteryx virgo_ and _C. splendens_. [Illustration: Fig. 55.--Calopteryx Virgo (Male).] TRIBE II.--SUBULICORNIA. The second tribe of the _Pseudo-neuroptera_ contains a group of insects which are so similar to one another in form that they are all included in one family. _Family 3, Ephemeridæ._--The _Ephemeridæ_, or Day Flies, as they are popularly called, are delicate, elongated, soft-bodied creatures, with a moderately small head. The antennæ, which spring from the forehead below the ocelli, are short and awl-shaped. These insects, which seem to be found mostly in temperate climates, are remarkable for the great delicacy of their structure, and for the extreme shortness of their lives in the perfect state, which seems in general scarcely to exceed a day. Nearly fifty species of _Ephemeridæ_ occur in this country. The best known is _Ephemera vulgata_, of which the sub-imago is called the "green drake," and the imago the "grey drake" by anglers. The two-winged _Clöen diptera_, which, however, is a much smaller species than the foregoing, is also very abundant. [Illustration: Fig. 56.--Calopteryx Virgo (Female).] TRIBE III.--PLECOPTERA. The _Plecoptera_ contain only one family. _Family 4, Perlidæ._--The _Perlidæ_, or Stone Flies, are chiefly inhabitants of the temperate regions; they are of small size, and not very numerous in species, about thirty being indigenous to the British Isles. The _larvæ_, which are aquatic in their habits, closely resemble the perfect insect in form. Their food consists of other insects and they prey especially upon the _larvæ_ of the Day Flies. The perfect insects are usually found resting quietly on plants and other objects on the banks of streams. The large brown species, _Perla bicaudata_, appears in the spring, and is very common in the neighbourhood of pools, streams, and canals. TRIBE IV.--CORRODENTIA. This tribe contains two families, one of which is represented in the British Isles. _Family 5, Psocidæ._--This is a family of small insects with simple veined wings. They have a rather large head, and bear a pair of long tapering antennæ. They are found upon trunks of trees, old palings, walls, etc. They are very active in their movements, and generally appear in the imago state about the end of summer or beginning of autumn.