112 



Rowland M. Shelley 



The milliped family Xystodesmidae, the dominant Nearctic 

 polydesmoid family, occurs in three general regions of the continent: 

 the eastern United States and southern Ontario and Quebec, Canada, 

 east of the Central Plains; from southern Texas and New Mexico to 

 El Salvador; and along the Pacific Coast west of the Sierra Nevada 

 and Cascade Mountains from Los Angeles to southern Alaska, with 

 an eastward extension into western Montana (Shelley 1987). The family 

 is also well represented in east Asia — Japan, the Riu Kiu Archipelago, 

 Korea, the vicinity of Vladivostok, Russia, and an unknown area in 

 central China (Hoffman 1978, 1979). Tribal continuity exists between 

 Meso-America and the eastern Nearctic, as the Rhysodesmini, the 

 only Meso-American tribe, is represented in eastern North America 

 by 9 genera and over 20 species. Similarly, the Orophini and Harpaphini 

 are represented in both the western Nearctic and Asiatic regions. There 



Fig. 1. Distribution of the Chonaphini. A smooth curve is drawn 

 around range extremes in all directions. Though no records are avail- 

 able from the interior of British Columbia, the western interior region 

 shows the projected occurrence of M. elrodi near the border with Idaho 

 and northeastern Washington. 



