REVISION MALACOSOMA HUBNER IN NORTH AMERICA 71 



the edge of the distributional hmits ; Hnes on forewings us- 

 ually with many indentations (figs. 270-277) which often 

 meet between the lines to cut off "islands" as in figure 270; 

 veins in forewings often outlined by whitish scales as in 

 figures 270 and 277; distribution — Mojave Desert area of 

 California, Arizona, Nevada, Utah, and the southern part 

 of the Great Basin (fig. 2) ; specimens may be found farther 

 south in California and in Mexico, too. 



calif ornicum fragile^ p. 164 



Color not as above, usually more orange-brown, yellow-brown 

 or gray-brown; lines on forewings sometimes with indenta- 

 tions, but rarely cutting off more than one "island" between 

 the lines; veins in forewings usually not outlined with scales; 

 distribution — western and northern North America, but not 

 from the Mojave Desert area outlined above, except along 



streams or irrigated areas 9 



9(8). Color medium brown to dark blackish, chocolate-brown (figs. 

 286 and 287), except for a few pale yellowish specimens with 

 brownish lines on forewings (fig. 285) ; distribution — the 

 Mexican plateau area as presently known. 



incurvum aztecum, p. 183 



Color variable, yellow-brown, gray-brown, yellow-gray or 

 chocolate-brown, but not occurring in the Mexican plateau 



area as presently known 10 



10(9). Color varying from yellowish-gray to dark gray-brown; lines 

 on forewings usually with small indentations along the veins 

 between the lines, or none, rarely with deeper ones (males in 

 figs. 291-308); distribution — mainly found along the Colo- 

 rado and Gila Rivers and their tributaries in the Utah- 

 Arizona area 11 



Color orange-brown, yellow-brown, or other shades of brown, 

 usually with little or no gray; lines on forewings with or 

 without indentations, but often with conspicuous ones which 

 may meet to cut off "islands" between the lines, especially in 

 specimens from the Great Basin, southern Rocky Mountains, 

 and the Southwest; distribution — western North America 



and northern Canada 12 



11(10). Color various shades of medium yellowish-brown; lines on 

 forewings usually brownish, and usually without indenta- 

 tions or only small ones (males in figs. 300-308) ; distribution 

 — lower parts of the Colorado River and its tributaries above 

 Hoover Dam (fig. 4) incurvum discolor atum, \>. Ill 



Color ranging from yellowish-brown to a blackish chocolate- 

 brown; lines on forewings light or dark, depending on the 



