REVISION MALACOSOMA HUBNER IN NORTH AMERICA 125 



median notch and sometimes with the lateroposterior tips more heavily 

 sclerotized so they appear to be "detached" from the main part. 

 Genitalia (fig. 36) indistinguishable from those of M. incurvum (fig. 35) 

 and quite variable; most similar in shape to those of americanum (fig. 

 31), but the absolute size of calif ornicum is smaller for moths of similar 

 size in other respects (compare the size of the eighth sternite of ameri- 

 canum (fig. 40) with those of calif ornicum in figs. 44—51). Also, the arc 

 of curvature of the "arms" of the eighth sternite near the points is 

 usually greater for calif ornicum than for americanum. Prongs of accessory 

 claspers (figs. 19-26) usually sharply pointed; distance between tips 

 of prongs variable, but usually equal to or less than their length as in 

 figure 23 for specimens from the Pacific Coast region and northern 

 Canada. Distance between the prongs usually greater than their 

 length as in figure 24 on specimens from other areas. However, con- 

 siderable variability is found, and intermediates such as figures 20 and 

 26 are not uncommon in both regions. 



ADULT FEMALES (females in figs. 176-284 except figs. 206- 

 208). — Color varying from reddish-brown to yellowish or grayish, 

 and many intermediate shades. Lines on forewings same as described 

 for the males, but if with indentations along the veins, they rarely 

 meet to form "islands" as in the males. Hindwing usually about same 

 color as forewing, but sometimes darker, especially on yellowish 

 specimens. Lower surface of both forewings and hindwings about same 

 color as ground color of upper surface, and both wings usually crossed 

 by a single contrasting line. Epiphysis absent or very small, usually 

 much smaller than second segment of foretarsus, if present. 



FEMALE TERMINALIA (figs. 91, 92, and 97-102).— Genital plate 

 varying from nonsclerotized to completely sclerotized ; ostium centrally 

 located. Ovipositor lobes with pronounced ventral and dorsal lobes as 

 in figure 100, or with the dorsal lobe reduced as in figure 98 in popula- 

 tions from the Pacific Coast and northern Canada. See "comments." 



ADULT DIAGNOSIS. — Many males can be separated from other 

 species by the color pattern, and in doubtful cases positive identification 

 can be made for all species except incurvum by the genitalic characters 

 given for each species. Specimens of incurvum cannot be positively sep- 

 arated from californicum by any known characters, but see the diagnoses 

 for incurvum (page 171), z. incurvum (page 174), and i. discolor atum (page 

 1 78) for suggestions as to the best way to separate both males and females. 

 Except for incurvum, male americanum are most likely to be confused with 

 californicum, but americanum can be separated by the larger absolute size 

 of the genitalia in relation to the size of the specimens, and by the arc 

 of curvature of the "arms" of the eighth sternite near the points. Also, 

 the total length of the eighth sternite almost always is distinctly greater 



