ATOPETHOLID MILLIPEDS — HOFFMAN AND ORCUTT 97 



We wish to acknowledge the cooperation in the loan of material 

 by Dr. H. W. Levi of the Museum of Comparative Zoology and by 

 H. S. Dybas and R. L. Wenzel of the Chicago Natural History 

 Museum. Dr. Ralph Crabill deserves our thanks for the loan of 

 paratypes from the U.S. National Museum and for the gift of 

 atopetholids that previously came into his hands. Dr. R. V. 

 Chamberlin very kindly examined some type specimens in his collection 

 in response to several appeals for information on structural details. 

 Our colleague H. F. Loomis, the describer of several atopetholids, 

 kindly gave valuable comparative material and advice concerning 

 some phases of the project. Finally, that the subfamily Eurelinae 

 is now the best known atopetholid group is attributable to the interest 

 and cooperation of Leslie Hubricht, whose collections provided the 

 initial stimulus for undertaking the project. 



Review of the Literature 



Apparently the first mem.ber of the Atopetholidae to be described 

 was the small Mexican species named lulus nietanus by Saussure in 

 1860. Owing to a lack of information on its sexual characters, this 

 species was subsequently placed first in the genus Spirobolus, then 

 into Cydothyrophorus, and finalh^, after a study of the type specimens, 

 was made the type of the genus Saussurobolus by Carl in 1919. 



The first generic name based upon an atopetholid is Onychelus 

 Cook, proposed in 1904 for a small spiroboloid from southern Cali- 

 fornia. Cook included Onychelus in the Spirobolidae, which he 

 considered at that time to be the only familj^ in the order Spirobolida. 

 The description of the genus and its tjrpe species, 0. ohustus, was fairly 

 detailed, but most unfortunately lacked illustrations and presented a 

 very vague description of the gonopods, conditions that subsequently 

 gave rise to considerable confusion. In a later paper (1911), Cook 

 described several additional genera and species, including Eurehts 

 soleatus, Centrelus falcatus, Onychelus dentatus, 0. hospes, and 0. 

 suturatus, the last three being species of the genus now known as 

 Arinolus. In this paper Cook also neglected to provide illustrations of 

 the genitalia, and considerable synonymy has resulted from subse- 

 quent inability to recognize his species with any degree of certainty. 

 One generic and two specific names must now be rejected as junior 

 synonyms because of the shortcomings of Cook's work, although the 

 verbal descriptions of bod}' form are as detailed and accurate as one 

 might wish. 



The family AtopethoHdae was erected in 1918 by R.V. Chamberlin 

 to include the new genera Atopetholus and Hesperolus, and also 

 "Onychelus, Eurelus, and related genera of the southwestern United 

 States and Mexico." In defining the family limits, Chamberlin relied 



