ATOPETHOLID MILLIPEDS — HOFFMAN AND ORCUTT 123 



as is known reflect a peculiarity of any rank of taxonomic group. In 

 our series of 12 male soleatus, 3 or 4 have one or the other of the 

 posterior gonopods protruded for various distances. 



There is no reason for maintaining Toltecolus parvunguis as a separate 

 species. The name was proposed in ignorance of Cook's 1911 paper, 

 and was set up as a new species on the basis of contrast with the 

 Mexican Toltecolus garcianus Chamberlin (=Centrelus kerrensis). 

 The description agrees in every particular with the material that 

 we have identified with Cook's E. soleatus. 



Distribution: The Coastal Plain of southern Texas, between the 

 Rio Grande and Colorado Rivers. The type specimens were taken 

 by Cook at Falfurrias, Brooks County, and he had additional speci- 

 mens from San Antonio, Bexar County, and Moore, Frio County. 

 The type of E. proximus is from Edinburg, Hidalgo County, and 

 that of T. parvunguis from Frio State Park, Frio County. The 

 series of millipeds at hand was collected along the highway 35.5 miles 

 northwest of Laredo, Webb County, May 29, 1955, by LesHe Hubricht. 

 This locality in the Rio Grande Valley is the westernmost now known 

 for the species. The occurrence of soleatus in adjacent parts of 

 Mexico, however, is certainly to be expected. 



Genus Centrelus Cook 



Centrelus Cook, 1911, p. 154. 



ToUecolus Charaberlin, 1943a, p. 27 (type species: Toltecolus garcianus Chamberlin). 



Type species: Centrelus falcatus Cook, by original designation. 



Diagnosis: A eureline genus similar to Eurelus, from which it 

 differs conspicuously in the presence of distinct upcurved spines on 

 the lower caudal edge of the pleurotergites. In the male sex the 

 anterior tarsal claws are reduced, and the coxal lobes well developed ; 

 coxites of the anterior gonopods with a large fleshy membranous lobe 

 near the apex on the anterior side. 



Discussion: The original generic diagnosis itemized external struc- 

 tural details at some length but touched only briefly on the genitalia, 

 and gave no illustrations of these appendages. Centrelus thereupon 

 slipped into a justifiable obscurity, and the name has not appeared 

 again in the literature. 



Texan material received from Leslie Hubricht agrees so closely with 

 the description of Centrelus that we have no doubt it is at least con- 

 generic with the type species. On this basis we have illustrated the 

 pecularities of the gonopods, and herewith suggest the identity of 

 Toltecolus with Centrelus, as well as some specific synonymy to be 

 discussed in a following paragraph. The type species C.falcatus Cook, 

 is from the State of Guanajuato; the other known species, C. kerrensis, 

 is known to occur in Nuevo Le6n and in western Texas, and suggests 



