REVISION MALACOSOMA HUBNER IN NORTH AMERICA 67 



Freeman (1949) pointed out that Malacosoma fragilis should properly 

 be Malacosoma fragile, since the gender of Malacosoma is neuter, not 

 feminine. Clisiocampa, the generic name under which most of the North 

 American species were originally described, is feminine, so the error 

 in endings is a natural one that came about when Malacosoma replaced 

 Clisiocampa as the proper generic name. 



The genus Malacosoma is a relatively homogeneous group which is 

 sharply distinct from other lasiocampid genera found in North 

 America. It has not been possible to examine representatives of all 

 other genera which occur in North America, but those which have been 

 examined {Gloveria, Eutachyptera, Dicogaster, Quadrina, Epicnaptera, 

 Artace, Tolype, Heteropacha^ Hypopacha, Nesara, and Euglyphis) differ 

 from Malacosoma in several respects. The monotypic genus Hypopacha 

 appears to be the nearest relative of Malacosoma in North America, 

 and Dyar (1928) says it forms a transition between Euglyphis (a large 

 Latin American genus) and Malacosoma. On the basis of adult morph- 

 ology alone, however, Hypopacha cannot be considered a close relative 

 of Malacosoma. 



The easiest way to identify specimens as Malacosoma is simply to 

 observe the overall shape and size in combination with the presence 

 of the two oblique lines on the forewings and the virtual lack of any 

 other distinctive markings (see figs. 119-329). Wing venation can be 

 used (fig. 10), but in practice this is rarely used because of the presence 

 of other, more easily visible characters. 



Four of the above genera {Gloveria, Eutachyptera, Dicogaster, Quadrina) 

 and also Caloecia (which has not been personally examined) can be 

 most easily separated from Malacosoma by their large size, males 

 having a wingspread of about 1 }^ to 2 inches, and females even larger. 

 Male Malacosoma never have a wingspread of m inches, and females 

 rarely approach 2 inches. In addition, all species of these genera 

 which have been examined have a small light-colored spot (sometimes 

 faint) located just beyond the discal cell in the forewing. This spot is 

 absent in Malacosoma. 



Epicnaptera is separated most easily by the scalloped margin of the 

 wings, especially the hindwing. The margin is relatively even in 

 Malacosoma. The remaining genera {Artace, Tolype, Heteropacha, Hy- 

 popacha, Nesara, and Euglyphis) are more nearly the same size as Mala- 

 cosoma, but they do not have the single pair of distinctive lines on the 

 otherwise unmarked forewings, or the wings are shaped diflferently. 

 In addition, vein R4 of the forewing arises at or beyond the apex 

 of the discal cell in species of these genera which have been examined, 

 but arises before the apex of the discal cell in Malacosoma (fig. 10). 



