REVISION MALACOSOMA HUBNER IN NORTH AMERICA 175 



calif ornicum females generally are more reddish-brown or orange-brown, 

 and the lines are more sharply contrasting as in the males. These 

 differences are admittedly poor, but there are no known structural 

 characters which will separate them. 



MATURE LARVAE (figs. 390-394).— Color quite variable, but 

 larvae are more easily identified than adults. Head mottled blue and 

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

 almost always v/ithout a stripe, but rarely with a faint, broken whitish 

 stripe which is most prominent anteriorly. Addorsal area varying from 

 black to orange. If the orange is conspicuous there is no whitish mid- 

 dorsal stripe of any kind, the orange is broken up into a pair of marks 

 which roughly resemble a pair of exclamation points ( ! !) on many 

 specimens, and the orange, together with the bordering black, forms 

 an oval-shaped mark on each segment (fig. 392). Subdorsal area 

 varying from bluish to nearly black on some specimens; other speci- 

 mens about half blue and half black, resulting in a longitudinal black 

 stripe which encompasses setal group SD at the lower edge of the 

 subdorsal area (fig. 393). Bluish specimens speckled with fi.ne black 

 spots at the bases of the secondary setae. Subdorsal line, if present, con- 

 sisting of only a pale yellowish mark on each segment immediately 

 ventral to the variable black area surrounding setal group SD. Supra- 

 spiracular area the same bluish color as subdorsal area in bluish speci- 

 mens; more gray-blue in blackish specimxns (fig. 394). Subspiracular 

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

 black, to nearly black, with a conspicuous median black area on lighter 

 specimens. Primary dorsal setae usually white, but sometimes yellowish; 

 secondary dorsal setae orange, but more golden on darker specimens. 

 Both primary and secondary lateral setae white, and secondary setae 

 conspicuously tufted around setal group L2. 



LARVAL DIAGNOSIS. — There is no positive way to separate all 

 incurvum incurvum from larvae of M. californicum, but i. inciirvum never 

 have a vertical black bar as far as is known, and they rarely have even 

 a faint middorsal stripe. Larvae of californicum may have a vertical 

 black bar, and often have a middorsal stripe. In addition, i. incurvum 

 larvae usually have the lateral setae conspicuously tufted about setal 

 group L2 (figs. 390-392), and larvae oi calif ornicum usually do not have 

 the lateral setae conspicuously tufted around setal group L2. 



Larvae of M. constrictum constrictum have apparently been confused 

 with i. incurvum in the past since constrictum has erroneously been reported 

 from Arizona. This has been due no doubt to the superficial resem- 

 blance in the dorsal orange markings of some i. incurvum, and the 

 tufting of the lateral setae in a way that is very similar to constrictum 

 (compare figs. 392 and 345). Larvae of constrictum can most easily be 



