REVISION MALACOSOMA HUBNER IN NORTH AMERICA 181 



COCOONS. — Cocoons are fairly tightiy constructed, usually without 

 an outer envelope of silk, and dusted with a whitish powder. 



FOOD PLANTS. — Egg masses were found on the following hosts: 

 Populus fremontii, Populus alba, Populus angustifolia, Salix sp., and apricot. 



TYPE. — Lectotype, here designated, a male in the United States 

 National Museum. USNM Type No. 33661. Size: 30 mm. wing- 

 spread. Damaged by dermestids, resulting in a hole in the right side 

 of abdomen. Data: Clisiocampa mus v. discolorata, B. Neumoegen, 

 Type; typicum specimen; S. W. Utah, C. I. Weidt; Lectotype, Mala- 

 cosoma mus v. discoloratum (Neumoegen), male, F. W. Stehr 1963. 

 Genitalia in microvial labeled : Lectotype, Malacosoma mus v. discoloratum 

 (Neumoegen), male genitalia, F. W. Stehr 1963. 



TYPE LOCALITY.— The original description lists the localities as 

 SW. Utah, and one female from Prescott, Arizona. This female from 

 Prescott is in the USNM and is actually a female M. californicum fragile. 

 The locahty "S. W. Utah" most likely refers to the area near St. George 

 along the Santa Clara and Virgin Rivers in Washington Co., Utah. In 

 the original description Neumoegen says, "raised out of a lot of about 

 50 typical mus by Mr. Chr. I. Weidt. It seems to be rare." The name 

 "mus" is a synonym of "fragile." It seems apparent that Mr. Weidt 

 collected a bunch of c. fragile larvae on the brush, and in doing so picked 

 up a few i. discoloratum larvae which had probably fallen from a nearby 

 Cottonwood, and which are quite similar in appearance to c. fragile 

 larvae. The lectotype falls within the range of variation of specimens of 

 /. discoloratum reared from cottonwoods growing near St. George, so the 

 type locality is restricted to St. George, Washington Co., Utah. 



PARALECTOTYPES.— There should be several females from SW. 

 Utah according to the original description, but these are not in the 

 USNM. The female from Prescott, Arizona, is M. californicum fragile. 



DISTRIBUTION.— As far as is known at the present time, i. dis- 

 coloratum seems to be restricted to the watercourses of the Colorado 

 River and its tributaries in the Canyonland area of Utah, extreme 

 western Colorado, and southeastern Nevada. It probably also occurs 

 in northwestern New Mexico along the San Juan and Chico rivers and 

 along the Colorado River in northern Arizona, but no specimens have 

 been collected or seen from these areas. Most likely it occurs along the 

 Colorado River in the Grand Canyon, but no tents were located on 

 cottonwoods along the Havasu River in the Havasupai Indian Reserva- 

 tion or in the area near Hoover Dam, although it was collected at 

 Mesquite, Nevada. Reports of tent caterpillars on cottonwoods in the 



