REVISION MALACOSOMA HUBNER IN NORTH AMERICA 131 



same brown color as egg masses found on Prunus virens growing nearby 

 (Coll. 247). None of the c^g masses collected from any locality in the 

 Chiricahuas contained any specks, however, although it would not 

 be surprising to find populations with specks if more intensive collecting 

 is done. The same situation occurred in Wyoming on aspen (Coll. 

 Nos. 360, 361, 363, and 364), but specks have never been found in any 

 egg masses collected on any host in Wyoming or more northern areas. 

 The situation in Colorado, New Mexico, southern Utah, and 

 northern Arizona is different. In these areas populations which feed 

 on various brush species growing beneath the aspen may have spuma- 

 line which contains specks. Other populations on the same brush 

 species may have no specks in their spumaline or reduced numbers of 

 specks. A comparison between these populations can best be made by 

 breaking them down into three subgroups as follows: 



1. Those which occur on aspen and whose spumaline contains no 

 specks (Coll. Nos. 308, 309, 437, 442, 443, 446, 449, and 450). These 

 are referred to as the "A" (aspen) population. 



2. Those which occur on brush species and whose spumaline con- 

 tains no specks (Coll. Nos. 439, 441, 444, and 448). These are referred 

 to as the "B" (brush) population. 



3. Those which occur on the same brush species and whose spumaline 

 contains specks (Coll. Nos. 306, 311, 438, 441a, 445, and 451). These 

 are referred to as the "BS" (brush-specks) population. These collections 

 were made in the Bryce Canyon National Park area and in the Kaibab 

 Plateau area north of the Grand Canyon, but similar situations may be 

 present wherever aspen is found within the area outlined in figure 5. 



In nearly every respect population B is closer to population A than 

 it is to population BS. The following comparison clearly shows this. 

 ADULT COLOR : malcs of all three populations were variable, but those 

 of A (figs. 255-259) showed various mixtures of reddish-browns, browns, 

 and yellows, with rarely any traces of gray. Male BS's were similarly 

 colored, but more frequently showed shades of gray in some localities. 

 Females of all three populations were various shades of dull medium 

 brown with relatively weak yellowish markings (fig. 260), and rarely 

 with a grayish tinge, size : Specimens of A and B were generally some- 

 what larger than BS specimens, but this may be the result of rearing 

 the BS's on nonnative hosts, since the natural host usually was not 

 available. Some of the B's, however, also were reared on non-native 

 hosts, and they were very close to the A's in size, so there may be a real 

 size difference between the smaller BS's and the larger A's and B's. 

 SPUMALINE : The spumaline of the A's and B's varied from tan to brown 

 and contained no specks; that of the BS's varied from gray to brownish 



