The second family (Japygidae) consists of one genus _Japyx_, of which there are, no doubt, several different species in various parts of the world, such having already been detected in tropical Africa, in Malasia, and in Mexico, as well as in Madeira and Europe. The commoner species of the latter continent, _Japyx solifugus_, lives in moss or in shady places on the edges of woods. It possesses a great resemblance to a newly-hatched earwig, and the writer has found it in France under a stone in company with a number of the tiny creatures it was so much like. This species has been found as far north as Paris, but has not been met with in Britain. The family Japygidae is, like the Campodeidae, entotrophous, and is distinguished by the body being terminated behind by a pair of forceps instead of antennary organs. The other two families of Thysanura, Machilidae and Lepismidae, are ectotrophous—that is, the parts of the mouth are not buried in the head, but are arranged in the fashion usual in mandibulate Insects. Only one genus of Machilidae is known, but it is no doubt very numerous in species, and probably is distributed over most of the globe. _Machilis maritima_ is common in some places on the coast of England. Another species (_M. polypoda_) occurs amongst dead leaves in the New Forest, and we have also observed a species of the genus under the loose stones that frequently form the tops of the "dykes" or piled walls in Scotland. In more southern Europe species of _Machilis_ are commonly met with on the perpendicular faces of very large stones or rocks, over which they glide with wonderful facility. The scales on the bodies of these rock-inhabiting species form pretty patterns, but are detached with such facility that it is almost impossible to obtain specimens in satisfactory condition for examination. In Machilidae the dorsal plates of the hind body are reflexed to the under surface so as to form an imbrication covering the sides of the ventral plates, and the eyes are largely developed; by which characters the family is distinguished from the Lepismidae. The pair of large compound eyes (Fig. 92, _O_) is a remarkable feature, being indeed unique in the Aptera. The structures (_o_, _o′_) that Oudemans considers to be simple eyes have, in external appearance, a resemblance to the fenestrae of the {185}Blattidae; Grassi states, however, that not only are they eyes, but that they are of almost unique structure, being, in fact, intermediate between simple and compound eyes.