114 Rowland M. Shelley 



tribes, and appear to relate to known chonaphines. One species, Montaphe 

 paraphoena, n. sp., occurring on the western periphery of the Columbia 

 Plateau in central Washington, has a modified acropodite that expands 

 distad and possesses a secondary projection. These features lend taxonomic 

 utility to the acropodite and suggest that additional forms with expanded, 

 modified acropodites, await discovery in central Washington. Because 

 of similarities with M. elrodi in coloration and the curvature patterns 

 of the telopodal elements, I provisionally assign this species to Montaphe 

 instead of erecting a fifth monotypic genus, although this action necessi- 

 tates a broad generic diagnosis resulting in a heterogeneous taxon. 

 Furthermore, Selenocheir, n. gen., with three species in southern Oregon 

 and northern/central California, is assigned to the Chonaphini even 

 though it has a short prefemoral process that is less than half the 

 length of the acropodite. The latter structure conforms to the tribal 

 diagnosis in being narrowly blade-like to acicular, but differences in 

 its orientation on the prefemur, in the broadness of its arc, and in the 

 distal configuration again lend it taxonomic utility. This genus is 

 more compatible with the Chonaphini than with any other western 

 xystodesmid tribe, and traits of the prefemoral process and acropodite 

 appear to represent plesiomorphic conditions that bridge anatomical 

 gaps with the Harpaphini. 



Thus the Chonaphini, which appears to be a homogeneous 

 assemblage characterized by a narrow, unmodified acropodite and a 

 long, elaborate prefemoral process, is really a highly variable ensemble 

 with few consistent, unifying features; even the structures of the cypho- 

 pods and the configurations of the gonopodal apertures vary widely. 

 Tubaphe and Selenocheir also lack a gonosternum, the coxae being 

 attached by membrane only, and those taxa with a sclerotized band 

 differ in the position of the sternal lobes. For example in M. elrodi, 

 the sternum is short, resulting in narrowly segregated gonopods, and 

 there are small lateral lobes subtending the coxae; in M. paraphoena 

 the sternum is also short and the gonopods are narrowly separated, 

 but there is an elongated medial lobe instead of two lateral ones. The 

 Chonaphini, therefore, is not united by a few features shared by all 

 included taxa but by a number of traits that are shared unevenly 

 among the components such that only one higher category can be 

 defined to encompass the scope of this variation. Efforts to divide the 

 group and render it more homogeneous by splitting off dissimilar 

 forms like Tubaphe and Selenocheir, which lack a gonosternum, or 

 just the latter, which has the short prefemoral process, or M. paraphoena, 

 with the medial sternal lobe and an expanded, modified acropodite, 

 result in undefinable categories that cannot be contrasted with a recon- 



