178 BULLETIN 38, UNITED STATES NATIONAL MUSEUM. 



both powdery, with incomplete common line and faiutl}' marked discal 

 lunule. Head and tliorax dark ; base of patagiie at sides ferruginous 



Expands 31-33'""'; 1.25-1.30 inches. 



Habitat. — Vancouver; California, Arizona. 



A short winged species, readily recognizable by the peculiar rusty and 

 black color and the very even pale t. jj. line. 



Group TESSELLATA. 



Front full, tuberculate or roughened ; anterior tibite spinose ; antenna3 

 of male serrate and bristled; thorax indistinctly or uot at all tufted, 

 rarely with a distinct anterior crest. Genitalia of the same type as in 

 the other groups of the genus. The distinguishing feature of the present 

 group is fountl in the ornamentation, and principally in the usually large, 

 often pale, ordinary spots, and the black or other dark stained cell reliev- 

 ing them. Negatively there is no distinct median shade, and there are 

 uo obvious dentations crossing or indenting the s. t. line. In the more 

 typical forms the primaries are perhaps a little broader and more trigo- 

 nate than in the typical forms of the other groups; but this does uot 

 hold true of all the species. 



As a whole the group is fairly well separable from the others of the 

 genus, but some of the species show variations which may create doubt. 

 Care is therefore necessary in placing single specimens of some forms, 

 and the general descriptions of ornamental and color characters must 

 not be too literally construed. 



\Vhereverpossible,a(iuestionableform should be compared with speci- 

 mens of the group types, and the relationshij) is then usually evident 

 and the chances of error are reduced to a minin)um. 



Of the species referred here fernaldi is at once separable by the broad, 

 even, blue gray transverse lines. It is a large wide-winged form and 

 very distinct. It seems also very rare. 



A small group of species of mountain or high northern habitat is 

 readily recognizable by luteous or gray color of primaries, hairy vesti- 

 ture, and simple transverse lines. These species have a distinctive hab- 

 itus, and are also well distinguished infer se. 



Opipara is ash gray with dark median space. The cell, claviform, 

 basal dash, and transverse line on collar are black. This is the species 

 mistaken by Moeschler and Staudinger for a variety of ulawUca. 



Tristicida has the basal dash and tlie black line on collar, but the trans- 

 verse maculation is obsolete and only the dark cell is })roininent. 



Munis, of which snhlatis is a synonym, lacks the black basal dash and 

 transverse line of collar. The median lines, however, are distinct, the 

 outer portion of median space is darker, and the ordinary spots are large, 

 distinct, concolorous. 



JDissona is closely allied, but less strongly marked ; an obvious distin- 

 guishing feature is founct in the woolly clothing of breast. In munis it 

 is white, in the present form black. 



