104 UNITED STATES NATIONAL MUSEUM BULLETIN 2 76 



86). Male constrictum are not so easily separated from tigris, but one 

 of the best ways to distinguish them is by distribution, since the 

 ranges do not overlap (compare fig. 1 with fig. 4). There are good 

 moi-phological characters, however, which will separate them. These 

 are given in the adult diagnosis for constrictum constrictum (page 94). 



Female tigris are most likely to be confused with those of constrictum 

 since females of both species are the only ones which are fairly dark 

 brown, and have the forewings crossed by dark lines and dusted with 

 whitish-yellow scales which are conspicuous to the unaided eye. Often 

 tigris can be distinguished from constrictum by differences in the color 

 pattern, but there are differences in the shape of the ovipositor which 

 will always separate them. When viewed laterally, the ovipositor of 

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

 separated by a distinct indentation. Female constrictum (fig. 86) have a 

 differently shaped ovipositor. See the adult diagnosis for constrictum 

 constrictum for a more com.plete description of these differences and for 

 differences in the color pattern (page 94). 



Female disstria also have dark lines on the forewings, but they can 

 usually be separated by color pattern differences and other differences 

 given in the adult diagnosis for disstria (page 86). Positive identification 

 of disstria can be made by the ovipositor lobes which are differently 

 shaped and have no distinct dorsal lobe (fig. 81). 



Occasionally rubbed or faded specimens of other species will be 

 encountered which are difficult to separate from tigris by color or color 

 pattern, but tigris can always be separated by the characters of the 

 ovipositor lobes given above. The ovipositor lobes of M. incurvum, 

 M. californicum, and M. americanum are always considerably larger if 

 specimens of the same wingspan are compared, and the lobes are 

 differently shaped (compare fig. 84 with figs. 88-103). 



MATURE LARVAE (figs. 342-344) .—Head nearly black, some- 

 times mottled with blue, and sparsely covered with fine black or 

 brownish setae. Dorsum of body without a contrasting whitish mid- 

 dorsal stripe or other distinctive middorsal markings such as are 

 present on some species. Dorsally each segment marked with a longi- 

 tudinal orange blotch which is narrowed in the middle, and somewhat 

 wider posteriorly than anteriorly. This orange blotch usually bears a 

 median blackish line, but in some specimens the entire blotch may be 

 virtually obscured by black. Subdorsal area basically black, but divided 

 into two longitudinal black stripes by a conspicuous, longitudinal, 

 wavy, orange line. (If the dorsal orange blotch is obscured by black 

 the more dorsal black stripe may blend into it.) Anterior section of 

 the more ventral black stripe marked with a variable blue patch which 

 may almost entirely obscure the black in some specimens. Both sub- 



