152. Maxilla.
The labium is much as in that of Perla, being broad and short, with a distinct median suture, indicating its former separation in embryonic life into a pair of appendages. The labial palpi are three-jointed, the joints being broad, and in life directed backwards instead of forwards as in the higher insects.
There are five American species of the genus Lepisma in the Museum of the Peabody Academy. Besides the common L. saccharina? there are four undescribed species; one found about out-houses and cellars, and the heat-loving form, perhaps an imported, species, found in a kitchen in Salem, and apparently allied to the L. thermophila Lucas, of houses in Brest, France; and lastly two allied forms, one from Key West, and another from Polvon, Western Nicaragua, collected by Mr. McNiel. The last three species are beautifully ornamented with finely spinulated hairs arranged in tufts on the head; while the sides of the body, and edges of the basal joints of the legs are fringed with them.
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.
153. Japyx solifugus.
The next family of Thysanura is the Campodeæ, comprising the two genera Campodea and Japyx. These insects are much smaller than the Lepismidæ, and in some respects are intermediate between that family and the Poduridæ (including the Smynthuridæ).
154. Campodea staphylinus.