The commonest British species is _Chrysis ignita_, which is a very variable insect, both as regards size and colouring. TRIBE III.--PHYTOPHAGA. The insects belonging to the third tribe of the Hymenoptera are strictly vegetable feeders. There are only two families. _Family 25, Siricidæ._--This family includes the insects known as Tailed Wasps. It is not a very extensive family, and its species occur chiefly in Europe and North America, in both of which regions the typical genus _Sirex_ is represented by large species. The best-known European species which is common in some parts of Britain is the great Tailed Wasp (_Sirex gigas_), a very formidable-looking insect, of which the female often measures nearly an inch and a half in length. [Illustration: Fig. 38.--Cimbex Luteus.] The general tint is black with the antennæ, the sides of the thorax and the legs and apex of the abdomen yellow. This insect lives in pine and fir woods, and the female deposits her eggs in the woody parts of the trees, into which she bores to a depth of over half an inch by means of her long ovipositor. [Illustration: Fig. 39.--Lophryus Pini (Mag.)] [Illustration: Fig. 40.--Pamphilius Faustus (Mag.)] Another species which occurs in this country is the _Sirex juvencus_, of a steel-blue colour, but smaller than the former. _Family 26, Tenthredinidæ._--This is a very extensive family and contains the numerous species of Saw Flies, so called because their ovipositor is in shape somewhat like a saw in appearance. Probably the best-known species is the Gooseberry Saw Fly (_Nematus ventricosus_), whose speckled and green _larvæ_ are so injurious in gardens and orchards. This insect is yellowish in colour, and about a quarter of an inch in length. _Tenthredo æthiops_, a small black species, deposits its eggs upon fruit trees. Many other species live on different kinds of plants and trees. ORDER NEUROPTERA. INCLUDING THE DRAGON FLIES, LACEWING FLIES, DAY FLIES, STONE FLIES, CADDIS FLIES, AND THEIR ALLIES. Next to the butterflies and moths, the _Neuroptera_ (or nerve-winged insects), to which belong the Dragon Flies, Lacewing Flies, Day Flies, Stone Flies, Caddis Flies, and their allies, are undoubtedly the most beautiful members of the insect tribe. Though they cannot compete with the _Lepidoptera_ in point of colouring, it is questionable whether they are not more graceful and elegant in appearance. The order _Neuroptera_ was founded by the great Swedish naturalist Linnæus, and its name has been kept intact since, though the classification of the insects comprised in it has undergone many modifications. [Illustration: Fig. 41.--Ascacaphus Macaronius.]