332 



in course, making it start close to the apex instead of about tlie middle 

 or outer third of the costa. At first sight the species look like separata^ 

 but the tibial armature, and indeed the maculation also, when carefully 

 studied, prove it to belong elsewhere. 



Tristyla, n. gen. — Head distinct; eyes large, rather prominent, globose, naked; 

 tongue well developed ; palpi well developed, closely scaled, oblique, extending to 

 or a little beyond the tip of the central frontal process ; front produced into a llat 

 plate which forms two short basal teeth to a long, pointed, central process exceeding 

 the head by its own length. The thorax is moderate, the vestiture scaly, close, except 

 that it forms a truncate, round, basal tuft. Abdomen somewhat exceeding the hind 

 angles of the secondaries, rather slender and closely scaled, untufted. Legs moder- 

 ately long, slender, with close scaly vestiture ; tibia unarmed except for the usual 

 spurs on the middle and hind pairs. Wings moderate, rather broad for their length; 

 primaries with the costa nearly straight, apex produced, acute, outer margin very 

 oblique, convex; venation apparently normal, the accessory cell present; second- 

 aries proportionate, the margins rounded, vein 5 as strong as the others. 



This genus belongs to the Acontiid series rather than to the Heliothids, and its 

 most distinctive character is the peculiar frontal structure. I recollect no other 

 Noctuid with a similar pronged process. 



Tristyla ALBOPLAGiATA, n. sp. (Fig. 46, 6). — Ground color white. Head with a 

 very narrow black line at base ; patagia with black scales toward their t\\) ; dorsum 

 of thorax luteous, posterior tuft white. Primaries with a narrow black basal line, 

 extending only to the subcostal vein. T. a. line geminate, the outer line black, nearly 

 upright, making three slight outcurves ; inner line grayish, shading off into a mixture 

 of gray and yellow scales which extends half way to the base. T. p. line single, 

 black, interrupted, irregularly lunulate, with a deep incurve below the cell. The 

 outer part of the median space is luteous gray except for a large, quadrate, white 

 costal patch, and this dusky shade extends to the s. t. line, which is narrow and irreg- 

 ular, defined primarily by the contrast between the s. t. and the white terminal 

 spaces. Apex grayish luteous. A broken dusky terminal line. Fringes white. The 

 claviform is wanting. Orbicular indicated by a few black scales. Eeniform marked 

 by a large, quadrate, white blotch, which extends from the costa to the median vein, 

 beneath which it is black margined, and from the middle or near it, to the outer 

 fourth of the costal margin. Secondaries smoky, immaculate. Beneath, primaries 

 blackish with narrow whitish margins ; secondaries white with an extra median 

 line and discal spot. 



Expands 18-20°^"^; 0.72-0.80 inch. 



Habitat. — Argus Mountains, April, 1891. 



I have three specimens, representing both sexes. This is a very 

 pretty insect and easily recognizable, not by its structural characters 

 alone, but by its markings as well. The base is white, limited by the 

 grayish luteous band extending to the t. a. line; a broad band of white 

 follows, and beyond this the dark color obtains to the s. t. line, except 

 for the large white costal patch which occupies the outer part of the 

 median space above the incurve of the t. p. line. The wing form and 

 habitus is not at all unlike Antaplaga at first sight, while the truncate 

 thoracic tuft and the close scaly vestiture implies Acontia. 



Omia nes^a, n. sp. (Fig. 46, 4). — Ground color very pale whitish green. Head and 

 thorax immaculate. Primaries immaculate, save that there is an oblique, broad, 

 diffuse, darker green median fascia, and a deeper tinge of the same color at the 



