THE MYRIAPODA OF NORTH AMERICA. 137 



1870. — I'etagrrpfM ('oj»e. TrauH. Amer. Ent. Soc, d'l {totalbn^). 



188<). — Uirutiinoma Fjiii/.uj;o. Hull. S<h'. Eut. Ital., 27n (palHdum). 



\HH7. — Hexaglcna McNeill. Proc. IJ. S. Nat. Mas., 328 (iriiptoaphala^^roHuIhum). 



From the above Hynoiiyiny it can be seen that I have united the 

 American 'j;enera PetanerpeH and Hexaglcna with the Kuiopcan j;cnus 

 PoJxfzoniuni. 



Concerning Petaserpea I wish to call attention to the following sen- 

 tence in Dr. Cojie's dia^rnosis : "Annula* without lateral ])roce8Kcs, each 

 with two pores, forming two rows on ca<'h side of the body." 



The tirst part implies that each annula has two pores, but his next 

 phrase that each has four instead of tiro. 



This obscurity of statement led Mr. McNeill to form his Hexaglcna, 

 which has only one row of foramina repugnatoria on ea<'h side of the 

 body, as was no doubt tlie case in Dr. Cope's specimens. 



.5. OCTOfJLF.NA. 



W&i.—Ovtog\ena Wood. Proc. Phila. Acad. Nat. Sci., 18fi (hirirgata). 



I have never seen a specimen belonging to this genus, but as it is 

 somewhat of a stumbling block, I call attention to the following }>oints: 



Judging from Dr. Wood's figures and some remarks by Dr. Cope, it 

 seems to me tliat Octoglena is closely related to Polyzoniutn, ))ut that it 

 ditfers in having the tirst dorsal plate not produced to the base of the 

 auteuna;, and the body much narrower than in Polyzonium. 



6. Platydesmi's. 



1843. — Platydesmiia Lucas. Ann. Soc. Ent. France, 51 (polydeamoide)). 

 1849. — Piestodesmus Lucas. Rev. vt. Mag. Zool., 589 (moreleti), 

 1864. — Brachycybe Wood. Proc. Phil. Acad. Nat. Sci., 187 (lecontei). 



The above nominal genera seem to agree in the shape of body, mark- 

 ings of segments, and structure of mouth parts, while the number ot 

 ocelli varies. Platydesmus has one, Piestodesmus has two, and Brachy- 

 cybe has none, but until all these points can be verified it is not safe to 

 form subgenera on this character. 



7. Stkmmiulus. 



1844. — Siemminhts Gorvais. Ann. Soc. Ent. France, 28 (biocitlatua). 

 1881. — St€mmijulu8 Karsch. Neue .Jul. Ber. Mas., als Prod. Jul. Monograph., ii 

 (emeud.). 



This genus has been ranked by Dr. Latzel as only a subgenus of 

 Jm/m«, but on account of the peculiar number of ocelli I believe it ought 

 to be given a full generic rank, at least until more can be ascertained 

 about the structure of the mouth parts. 



The original orthography of Gervais should be employed. 



