60 Rowland M. Shelley 



Another unusual feature of arcuatus is the presence of both simple 

 and reflexed tips. I know of no other apheloriine species possessing such 

 broad variation, and I consider the forms in Figures 3 and 5 to be con- 

 specific because material from intervening areas in Anderson County 

 displays intermediate conditions. The reflexed tips in Abbeville speci- 

 mens of arcuatus, coupled with the medial flanges in arcuatus and some 

 forms of shelf ordi, are evidence of affinity with Sigmoria. However, the 

 more proximal location of the flange on the basal zone in arcuatus and 

 shelfordi, plus the spine at the base of the acropodite in these two spe- 

 cies, justify generic separation from Sigmoria. 



I include with arcuatus the geographically and anatomically dis- 

 junct males from Oconee County listed with shelfordi in my 1980 paper. 

 Lacking a prefemoral process, and possessing a stronger basal spine and 

 more broadly curved acropodite than other males of shelfordi, these 

 males conform more to the description of arcuatus. However, they also 

 differ from other specimens of arcuatus in having more massive gonop- 

 ods, broader medial flanges, reduced acropodal curvatures, and broader 

 tips. Perhaps there is a third species of Brevigonus in Oconee County, 

 which is unknown except for these specimens. Several trips to Clemson 

 and areas in Oconee County, however, have failed to produce more 

 individuals, and I therefore include this sample under arcuatus pending 

 discovery of additional material. 



ACKNOWLEDGMENTS.— This study was supported in part by 

 NSF Grant DEB 7702596. Thanks are extended to Renaldo G. Kuhler, 

 NCSM scientific illustrator, for preparing Figure 2. 



LITERATURE CITED 



Chamberlin, Ralph V., and Richard L. Hoffman. 1958. Checklist of the 

 millipeds of North America. U. S. Natl. Mus. Bull. 2/2:1-236. 



Hoffman, Richard L. 1967. Revision of the milliped genus Cleptoria (Polydes- 

 mida: Xystodesmidae). Proc. Biol. Soc. Wash. 724:1-27. 



Loomis, Harold F. 1944. Millipeds principally collected by Professor V. E. 

 Shelford in the eastern and southeastern states. Psych 51: 166- 177. 



Shelley, Rowland M. 1977. The milliped genus Croatania (Polydesmida: Xys- 

 todesmidae). Proc. Biol. Soc. Wash. 90:302-325. 



1980. The status of Cleptoria shelfordi Loomis, with the proposal of 



a new genus in the milliped family Xystodesmidae (Polydesmida). 

 Brimleyana 3:31-42. 



1981a. Revision of the milliped genus Sigmoria (Polydesmida: Xys- 

 todesmidae). Mem. Am. Entomol. Soc, No. 33, 140 pp. 



1981b. A new xystodesmid milliped genus and three new species from 



piedmont South Carolina (Polydesmida). Proc. Biol. Soc. Wash. 94:949-961. 



Accepted 17 November 1981 



