The interesting genus Nicoletia stands at the bottom of the group. It has the long, linear, scaleless body of Campodea, in the family below, but the head and its appendages are like Lepisma, the maxillary palpi being five-jointed, and the labial palpi four-jointed. The eyes are simple, arranged in a row of seven on each side of the head. The abdomen ends in three long and many jointed stylets, and there are the usual "false branchial feet" along each side of the abdomen. There are two European species which occur in greenhouses. No species have yet been found in America. [Illustration: 153. Japyx solifugus.] The next family of Thysanura is the Campodeae, comprising the two genera Campodea and Japyx. These insects are much smaller than the Lepismidae, and in some respects are intermediate between that family and the Poduridae (including the Smynthuridae). In this family the body is long and slender, and the segments much alike in size. There is a pair of spiracles on each thoracic ring. The mandibles are long and slender, ending in three or four teeth, and with the other appendages of the mouth are concealed within the head, "only the tips of the palpi (and of the maxillae when these are opened) projecting a very little beyond the rounded entire margin of the epistoma," according to Haliday. The maxillae are comb-shaped, due to the four slender, minutely ciliated spines placed within the outer tooth. The labium in Japyx is four-lobed and bears a small two-jointed palpus. The legs are five-jointed, the tarsi consisting of a single joint, ending in two large claws. The abdomen consists of ten segments, and in Campodea along each side is a series of minute, two-jointed appendages such as have been described in Machilis. These are wanting in Japyx. None of the species in this family have the body covered with scales. They are white, with a yellowish tinge. The more complicated genus of the two is Japyx (Fig. 153, Japyx solifugus, found under stones in Southern Europe; _a_, the mouth from beneath, with the maxillae open; _b_, maxilla; _d_, mandible; _c_, outline of front of head seen from beneath, with the labial palpi in position) which, as remarked by the late Mr. Haliday (who has published an elaborate essay on this genus in the Linnaean Transactions, vol. 24, 1864), resembles Forficula in the large forceps attached to its tail. An American species (J. Saussurii) lives in Mexico, and we look for its discovery in Texas. [Illustration: 154. Campodea staphylinus.] Campodea (C. staphylinus Westw., Fig. 154, enlarged; _a_, mandible; _b_, maxilla), otherwise closely related, has more rudimentary mouth-parts, and the abdomen ends in two many jointed appendages. [Illustration: Fig. 155. Larva of Perla.]