96 PROCEEDLNTGS OF THE NATIONAL MUSEUM vol. in 



only from type specimens which are now lost or otherwise inaccessible. 

 Obviously, a large number of species and probably additional genera 

 remain to be discovered and integrated into the existing system, 

 which thus stands vulnerable to future modification and expansion. 

 The geographic range of no single species can presently be mapped 

 with any sort of precision. 



These facts might suggest that the present synopsis is founded 

 upon an undue measure of presumption. Actually, there is every 

 justification for immediate attention to whatever problems can be 

 solved or even defined with the material at hand, for it is essential 

 that the confusion be resolved and the classification stabilized as 

 soon as possible before additional Imowledge is superimposed on the 

 currently shaky framework. 



In this paper we have endeavored to phrase some tangible defini- 

 tions for the family as well as for subfamily and generic categories, 

 to clarify gonopod structure and thus establish a basis for future 

 studies of comparative morphology, and to evaluate some of the 

 structural variables which have been used to recognize species. 

 Where material has permitted, we have redescribed both species and 

 genera in detail, and have emphasized some characters normally over- 

 looked. The level of thoroughness of this phase is noticeably uneven, 

 for, lacldng specimens, almost nothing could be done with the sub- 

 family Atopetholinae. Nonetheless, this paper lays some claim to 

 distinction in being the only one of its kind yet essayed for a family 

 of millipeds.^ We trust that our paper will be useful to those 

 interested in describing and collating om* native milliped fauna, one 

 of the most diverse in the world, and will constitute a first step toward 

 an eventual monograph of the great order Spirobolida. 



Materials and Acknowledgments 



Although the quantity of specimens that we have examined is not 

 great, it nonetheless is quite diverse and gives a fair cross section 

 of the family. We have studied 9 species representing 7 of the 11 

 known genera and all of the 4 subfamilies here recognized, and as a 

 result have been able to utilize accounts in the literature of other 

 genera with some degree of confidence. The validity of specific 

 concepts has been enhanced by the abundance of typical material, 

 one of the species being represented by a topotype, three others by 

 paratypes, and two more — here described as new — by the holotypes. 

 All of these type specimens as well as material of the other species 

 are in the collection of the U.S. National Museum. 



» A detailed study of the family Spirobolldae, by Dr. William T. Keeton, Is now being prepared for pubU- 

 oatlon. 



