144 



THE MYRIAPODA OF NORTH AMERICA. 



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 arc 

 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 Iithobiidffi the structure of the under portion of the head is 

 almost identical with that described above. 



Among the Geophilidffi 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 maxilla are apparently wanting, but the 

 maxillary palpi are recognizable. Among the Cermatiidse 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 arc otherwise enormously developed, espe- 

 cially as to length. The palpi arc very long. The maxillse and maxillary palpi are well 

 developed. 



Sub Ord. SCHIZOTARSIA.* 

 Antennae longissimx, setaceos, cum tarsis multiarticulatao. Oculi eompositi. 

 Antenna) very long, setaceous, together with the tarsi multiarticulatc. Byes compound. 



Fam. I. CERMAT UDM, Leach. 



Scuta 8. Segmenta 16. Sterna 16. Scutorum stomata mediana. Pedes antenrm-quc multiarticulatao. 

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



In the Cermatiidtc 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 elon- 

 gate and spinous. The antenna? very long, and composed of a multitude of joints. The 

 mandibles are elongate and distant. The scuta (eight in number) arc 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 ser- 

 rated by parallel rows of spinulao. They are also furnished with rings, of long slender 



* Brandt, Recueil, p. 26. 



