REVISION ]\L\LACOSOMA HUBNER IN NORTH AMERICA 171 



ADULT DIAGNOSIS. — Male incurvum usually can be separated 

 from male M. californicum fragile by the more yellow-brown colors of 

 incurvum in the localities where they occur together, compared with the 

 more yellow-gray or whitish-gray colors of c. fragile. Also, male c. 

 fragile usually have the lines on the forewings more conspicuously in- 

 dented along the veins so they cut off "islands," while incurvum males 

 have no indentations or less conspicuous ones which rarely meet to 

 cut off "islands." Females are more difficult to separate, but female 

 incurvum genercJly are more uniform brown or yellowish-brown, and the 

 lines on the forewings are more even with small indentations along the 

 veins. Female c. fragile are generally paler, with a distinct gray or 

 whitish-gray appearance, and the lines on the forewings are less even 

 and with more jagged indentations. 



There is no good way to separate other populations of M. californicum 

 from incurvum except that in general, both male and female californicum 

 are more reddish to orange-brown than incurvum. Specimens which 

 cannot be placed with certainty in either species are bound to be en- 

 countered, but, as has been pointed out (page 118), the relationships be- 

 tween incurvum and other populations of californicum are incompletely 

 known, and reproductive isolation does not appear to be completely 

 developed, so these intermediate specimens are to be expected. All 

 other species (americanum, dissfria, tigris, and constrictum) can be easily 

 identified by the diagnostic characters given for them. 



MATURE LARVAE (figs. 390-399).— Variable, but not as highly 

 variable as M. californicum throughout its range. Head mottled blue 

 and black, sparsely covered with whitish setae. Middorsal area black, 

 with or without a blue-white to bluish line. Addorsal areas varying 

 from black to orange ; if the orange is conspicuous it often resembles a 

 pair of exclamation marks (!!) on each segment as in figure 392. Sub- 

 dorsal area varying from blue to blue-green to blue-gray or black. Sub- 

 dorsal line, if present, consisting of only a pale yellowish mark on each 

 segment immediately ventral to a variable black area surrounding setal 

 group SD. Supraspiracular area same bluish color as subdorsal area, 

 or more blue-gray if subdorsal area is largely black. Subspiracular area 

 pale whitish blue-gray. Ventral area mottled gray-white and black to 

 nearly black, with a conspicuous black median area on lighter speci- 

 mens. Primary dorsal setae yellowish to white; secondary dorsal setae 

 orange. Primary and secondaiy lateral setae white, and conspicuously 

 tufted around setal group L2 in some populations. 



LARVAL DIAGNOSIS. — There is no easy way to separate larvae 

 of incurvum from those of M. californicum, but see the diagnosis under 

 M. incurvum discoloratum (page 1 79) and M. incurvum incurvum (page 1 75) for 

 the best ways to separate the larvae in the areas where these subspecies 



279-280— 6S 12 



