The forms composed in this tribe of insects are reckoned at present to be the nearest resemblance to the theoretical progenitors of the insects; in fact, Sir John Lubbock hints that they might well be regarded not as insects at all, but rather as the surviving representatives of a group formed by the ancestors of the whole multitude of insect types. [Illustration: Fig. 62.--Lepisma Saccharina (Mag.)] [Illustration: Fig. 63.--Orchesella Rufescens (Mag.)] The food of these creatures consists of decayed vegetable matter. Three principal families may be recognised--viz., _Lepesmidæ_, _Campodeidæ_, and _Japygidæ_. TRIBE IX.--COLLEMBOLA OR SPRING TAILS. These insects closely resemble the previous tribe in general character, to which also the same remarks nearly apply. They are generally small insects, a length of a quarter of an inch being considerably above the average. They are found commonly in loose earth, under decaying leaves in woods, in moss, under the bark of dead trees, and in rotten stumps. They always prefer damp situations. [Illustration: Fig. 64.--Isotoma Gervaisi (Mag.)] Cold seems to have but little effect upon them; they will recover their activity after being frozen. One species, _Desoria glacialis_, is found enjoying itself upon the Swiss glaciers, and another, _Degeeria nivalis_, occurs upon the surface of snow in many parts of Europe. Some species also may be met with hopping about upon the surface of standing water. _Podura aquatica_, a minute blue-black species, is common in such situations in England. The five principal families are the _Smynthuridæ_, _Papyriidæ_, _Degeeriadæ_, _Poduridæ_, and the _Amouridæ_. ORDER ORTHOPTERA. INCLUDING THE GRASSHOPPERS, LOCUSTS, CRICKETS, COCKROACHES, EARWIGS, AND THEIR ALLIES. The _Orthoptera_ include all those forms of insects which have four wings, the anterior pair being of a leathery nature. They are mandibulate; that is, their mouths are formed for biting, and they undergo an imperfect metamorphosis. The insects comprised in this order are extremely numerous and destructive in the tropical parts of the world (Kirby gives their number as about 7,000), but they are only represented in the British Isles by about sixty species, few of which are really abundant. They include the cockroaches, crickets, grasshoppers, locusts, earwigs, etc. All these insects may be divided into three sub-divisions or tribes--namely, the Runners or _Cursoria_, the Leapers or _Saltatoria_, and the Earwigs or _Euplexoptera_. The following table will show at a glance the outlines of the proposed arrangement:-- _Tribe_ I., _Cursoria_.--Hind wings with veins radiating from the base. Hind legs formed for running. _Tribe_ II., _Saltatoria_.--Hind wings with veins radiating from base. Hind legs formed for leaping. _Tribe_ III., _Euplexoptera_.--Hind wings with veins radiating from the apex of a horny piece occupying the base of the anterior margin.