MILLIPED GENUS DIXIORIA — ^HOFFMAN 3 



such an elamentary precaution has been one of the outstanding defects 

 of American diplopod taxonomy. 



For the privilege of studying the collections under their care, I 

 am indebted to Dr. E. A. Chapin, formerly of the U. S. National 

 Museum, Dr. Willis J. Gertsch of the American Museum of Natural 

 History, and Dr. P. J. DarUngton of the Museum of Comparative 

 Zoology. Gordon K. MacMillan Idndly loaned all of the Appalachian 

 millipeds in the Carnegie Museum, including several interesting series 

 of different forms. 



Most of my field work was done with the aid of grants from the 

 Virginia Academy of Sciences and the Highlands (North CaroHna) 

 Biological Station. James A. Fowler, Hubert I. Kleinpeter, and 

 William T. Keeton have been helpful companions in the field. 



More than to anyone else, this study of Dixioria owes its existence 

 to my good friend Leslie Hubricht, an outstanding student of American 

 gastropods and an unexcelled collector, who has provided perhaps the 

 largest part of the material in my collection. 



Review of the Literature 



A certain amount of confusion presently attends usage of the 

 generic names Ddtotaria and Dixioria. I have personally contributed 

 to this misunderstanding, and am glad to take the opportunity to 

 review the status of the two groups with the hope of correcting previous 

 mistakes. 



The genus Deltotaria was proposed by Causey in 1942 for the recep- 

 tion of a new species (brimleii) collected at Swannanoa, N. C. The 

 primary diagnostic character cited for the genus was the presence of 

 a projection on the coxal joint of the gonopod. Somewhat later, two 

 additional species were described, D. nigrimontis (Chamberlin, 1947) 

 and D. coronata (Hoffman, 1949). Apparently both Chamberlin and 

 I were impressed by the fact that the distal end of the gonopod in our 

 species was similar to that figured for brimleii (furcate), and we over- 

 looked the complete absence of a coxal projection in our new forms. 

 With the initiation of intensive studies on the genera of the Xystodes- 

 midae, it became apparent that members of two considerably different 

 genera had been described under the name Deltotaria. More recently, 

 Dr. Causey published the descriptions of two additional species, both 

 of which agree with the generotype, thus emphasizing the misplace- 

 ment of coronata and nigrimontis. 



At first it appeared that a new generic name was needed to embrace 

 these two orphaned species, which seemed to fit into none of the cur- 

 rently recognized genera. Soon, however, I discovered that Dixioria 

 of Chamberlin (1947) was available for one of them because its type 

 species is subjectively congeneric with coronata, and that the other is 



