REVISION MALACOSOMA HUBNER IN NORTH AMERICA 95 



ovipositor lobes is quite different, however, and positive identification 

 can be made by them. When viewed laterally, the ovipositor of tigris 

 (fig. 84) has evenly rounded dorsal and ventral lobes which are 

 separated by a distinct indentation. In lateral view the ovipositor of 

 constrictum (fig. 86) diffei's in having both dorsal and ventral lobes 

 more pointed and in having at most, only a small, differently shaped 

 indentation separating them. Also compare the posterior views of the 

 ovipositors (figs. 85 and 87). There is a conspicuous convergence of the 

 ovipositor lobes below the anus of comtrictum, but there is little or no 

 such convergence in tigris (or in disstria, either, fig. 82). In addition, 

 the ovipositor apodemes of constrictum (fig. 86) are usually only slightly 

 widened near the middle, while those of tigris (fig. 84) and disstria 

 (fig. 81) usually are widened distinctly near the ovipositor. The 

 apodemes of other species vary considerably, so this character should 

 only be used as an aid in separating constrictum from tigris and disstria^ 

 and not in separating it from other species. 



Differences in the color pattern are of limited value in distinguishing 

 female constrictum and tigris. Generally, the median area on the fore- 

 wings of constrictum is the same color or only slightly darker than the 

 inner and outer areas, while the median area oUigris is usually definitely 

 darker than the inner and outer areas. In constrictum the distance between 

 the lines at the inner margin of the forewing is generally less than the 

 distance between the inner line and the base of the wing at the inner 

 margin, while in tigris the distance between the lines at the inner 

 margin customarily is greater than the distance between the inner 

 line and the base of the wing. Also, the outer line on constrictum is 

 usually bent inward near the middle more than it is on tigris where it 

 generally is nearly straight. These differences are admittedly slight 

 and not entirely reliable, but positive identification can be made by 

 the ovipositor lobes if there is any doubt. 



MATURE LARVAE (figs. 345, 347).— Head mottled blue and black, 

 sparsely covered with fine, black setae. Dorsum without a contrasting 

 whitish stripe or other distinctive middorsal markings such as are 

 present on some species. Dorsally each segment marked with irregular, 

 orange, wavy lines intermixed with black and creating a more or less 

 hourglass-shaped orange blotch which is bordered on both sides by a 

 conspicuous round black spot surrounding setal group Dl. Subdorsal 

 area aquamarine to blue and speckled with black. Siipraspiracular 

 area mixed bluish and grayish with an irregular, longitudinal cream- 

 colored splotch just ventral to setal group SD on each segment. Area 

 surrounding setal group L2 whitish. Subspiracular area blue-gray to 

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

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



