Page:Wood 1865 - The Myriapoda of North America.djvu/9

144 anterior portion of the labium, which I have frequently seen separated by a suture, being composed of the episterna and primitive sterna of the same subsegment. The mandibles are probably the appendages of the third basilar subsegment, the posterior portion of the labium being composed of the sterna of the same subsegment. Two plates, which are bent round the sides of the posterior portion of the labium, may be the episterna. The sternal portions of the fourth basilar subsegment are similar to those of the segments of the body. Among the Lithobiidæ the structure of the under portion of the head is almost identical with that described above. Among the Geophilidæ the parts of the mouth are so consolidated and confused that it is impossible to recognize in the adult the original plan of construction and development. On examining the under surface of the head of a Mecistocephalus, we will find the labium very large, as are also the mandibles, while the maxillæ are apparently wanting, but the maxillary palpi are recognizable. Among the Cermatiidæ the labium is moderate, cleft in the middle, the two lateral halves being movable on one another, so as to form as it were an additional joint to the mandibles; which are otherwise enormously developed, especially as to length. The palpi are very long. The maxillæ and maxillary palpi are well developed.

SCHIZOTARSIA. Antennæ longissimæ, setaceæ, cum tarsis multiarticulatæ. Oculi compositi.

Antennæ very long, setaceous, together with the tarsi multiarticulate. Eyes compound.

CERMATIIDÆ, Leach. Scuta 8. Segmenta 16. Sterna 16. Scutorum storaata mediana. Pedes antennseque multiarticulatæ.

Scuta 8. Segments 16. Stomata of the scuta median. Feet and antenna multiarticulate.

In the Cermatiidæ the head is large, more or less truncate anteriorly, having its surface rough and uneven. The eyes are compound and very prominent. The palpi very elongate and spinous. The antennæ very long, and composed of a multitude of joints. The mandibles are elongate and distant. The scuta (eight in number) are rounded and deeply emarginate posteriorly, where they are furnished with a longitudinal, slit-like orifice or stoma. Their surface is more or less roughened with minute tubercles or spines. Their border is everted, and generally crenulate and spinous. The legs are very long, and serrated by parallel rows of spinulæ. They are also furnished with rings, of long slender