Owing partly to the inherent difficulties of the subject, and partly to the fragmentary manner in which it has been treated by systematists, it has been impossible till recently to form any clear idea of the classification of Orthoptera. During the last twenty years Henri de Saussure and Brunner von Wattenwyl have greatly elucidated this subject. The latter of these two distinguished naturalists has recently published[128] a revision of the system of Orthoptera, which will be of great assistance to those who may wish to study these Insects. We therefore reproduce from it the characters of the tribes, placing the portion relating to each family at the end of our sketch thereof. FAM. I. FORFICULIDAE—EARWIGS. (DERMAPTERA OR DERMATOPTERA OF BRAUER AND OTHERS) _Insects of elongate form, with an imbricate arrangement of the segments of the body; bearing at the posterior extremity a pair of callipers or more distorted instruments. The hind wings (when present) folded in a complex manner, and covered, except at their tips, by a pair of short wing-covers (tegmina), of a leather-like consistence. Wingless forms are very numerous. The young is very similar to the adult._ [Illustration: FIG. 102.—_Pygidicrana hugeli._ Java.] Although earwigs are said to be rare in most parts of the world, yet in Europe no Insect is better known than _Forficula auricularia_, the common earwig, it being very abundant even in gardens and cultivated places. In certain seasons it not unfrequently enters our houses, in which case it too often falls a {203}victim to prejudices that have very little to justify them. This Insect is a good type of the winged earwigs. In the parts of the mouth it exhibits the structures usual in the Orthoptera; there is a large labrum, a pair of maxillae, each provided with two lobes and a palpus consisting of two very short basal joints and three longer joints beyond these; the mandibles are strong, with curvate pointed extremities; in the lower lip there is a ligula exposed in front of a very large mentum; it consists of two pieces, not joined together along the middle, but each bearing on its lateral edge a palpus with two elongate joints and a short basal one; this lip is completed by the lingua, which reposes on the upper face of the part, and completely overlaps and protects the chink left by the want of union along the middle line of the external parts of the lip. The antennae are elongate, filiform, and are borne very near the front of the exserted head. There are rather large facetted eyes, but no ocelli. The three segments of the thorax are distinct, the prothorax being quite free and capable of movement independent of the parts behind it: the meso- and meta-nota are covered by the tegmina and wings; these latter project slightly from underneath the former in the shape of small slips, that are often of rather lighter colour; the wing-covers are short, not extending