350 AMERICAN LEPIDOPTERA. 



single hook of the bicolorago series, and the structure is constant 

 and not confined to this series of species only. The species as a 

 whole are slighter bodied than those of the preceding series; but the 

 differences are so slight that it is difficult to draw the line. The 

 costa of primaries is always arched, and generally the inner margin 

 as well ; but aggressa, in wing form, is very like antapica, except 

 that on the secondaries there is a mere trace of the subapical exci- 

 sion. The harpes of the males vary quite a little ; that of aggressa 

 resembling the preceding series quite nearly, while that of r alia has 

 a series of spinules on the inner side of the tip. All the species 

 agree in having as clasper a long, slender or moderate curved hook. 



Aggressa Smith is the palest of the species, and in wing form 

 most like those of the previous series. In fact, taking only the first, 

 superficial impression as controlling, its reference as an ally of pur- 

 purea is the most natural. It is the palest in color of all the spe- 

 cies, and in the terminal space in some examples there is a distinct 

 wash of whitish. The median shade is especially well marked and 

 is nearer to a real band than in any other of the species. The sec- 

 ondaries are dirty gray or even whitish, and, altogether, this is a 

 well defined form. The harpes of the male are drawn to a blunt 

 point from the inferior margin, and there is no spinulation at tip, 

 though there are isolated long bristles at the margin. The clasper 

 is moderate in length, stout, well curved, with a blunt tip. 



Earoa Grote is a distinctly redder gray to brownish form, with 

 shorter primaries, which have in the male always, and in the female 

 usually, arched costal and inner margins. In some of the females 

 the reddish gray predominates, all the maculation is well written, 

 and the appearance is very like that of the preceding species, save 

 for the tendency to a dark terminal space and the reddish shade. In 

 the males this narrow winged paler form does not appear to occur, 

 and there is no difficulty in recognizing it. The secondaries are 

 dirty whitish to smoky, with a pinkish or faint reddish tinge. In 

 the male the harpes are shorter and broader than in its allies, the 

 tip more obtuse and the margins set with longer, stiff bristles. The 

 clasper is very long, more slender than in any other species, and 

 well curved. 



Duscata Smith looks at first sight like a smaller, darker euroa, in 

 which there is a tendency to a blackish shading; and with males of 

 euroa only at hand for superficial comparison, that conclusion would 



