REVISION MALACOSOMA HUBNER IN NORTH AMERICA 99 

 Malacosoma constrictum austrhium Stehr, new subspecies 



ADULTS (figs. 152-160). — The description and diagnosis for adults 

 of M. constrictum constrictum (page 93) apply equally well to this sub- 

 species, except that the males are usually more heavily dusted with 

 brown scales, often being nearly as brown as the females. Some males, 

 however, may be as light as specimens of constrictum constrictum. In 

 addition, the lines on the forewings of both males and females are 

 often poorly defined. 



This subspecies is recognized on the basis of very striking and con- 

 sistent differences in the larvae from southern California compared 

 with those which occur farther north. The laivae of constrictum austrinum 

 (figs. 346 and 348) are structurally the same as constrictum constrictum, 

 but the color of the lateral setae is orange instead of white, the head is 

 largely black instead of mottled blue and black, and the proportions 

 of the colors making up the color pattern are considerably different. 



MATURE LARVAE (figs. 346 and 348).— Head black, with little 

 or no blue, sparsely covered with fine orange and black setae. Dorsum 

 without a contrasting whitish stripe or other distinctive middorsal 

 markings as are present on some species. Dorsally each segment marked 

 with irregular orange, wavy lines intermixed with much black and 

 creating a more or less hourglass-shaped blotch which is bordered on 

 both sides by a round black spot surrounding setal group Dl. Subdorsal 

 area deep blue, but partially obscured by black which also tends to 

 obscure the round black spots surrounding Dl. Supraspiracular area 

 mixed blackish, dark gray, blue-gray and orange, with a very con- 

 spicuous longitudinal, irregular, orange splotch just ventral to setal 

 group SD on each segment. Area surrounding setal group L2 yellowish- 

 orange. Subspiracular area dark gray to gray, sometimes faintly blue- 

 gray. Ventral area mottled gray-black and white, usually with a 

 median black spot on each segment. Primary doi'sal setae long and 

 black anteriorly, sometimes tending to be orange posteriorly; secondary 

 dorsal setae orange and conspicuously tufted anteriorly and posteriorly 

 on each segment. Lateral setae orange, and conspicuously tufted 

 around setal group L2 on each segment. 



LARVAL DIAGNOSLS. — Larvae of M. constrictum austrinum can 

 easily be separated from those of Af. constrictum constrictum by the orange 

 lateral setae and the much greater amount of orange and black in the 

 color pattern which tends to obscure the blue that is so striking in 

 constrictum constrictum (compare figs. 346, 348 with 345, 347). 



The larvae most likely to be confused with it are those of M. cali- 

 fornicum californicum (figs. 352 and 353) and possibly other variants 



