no. 1753. NORTH ll//.7.'/ri\ GEOMETR1D MOTHS— GROSSBECK. 375 



color. Median area decided yellow to brown, intensified from center 

 to outer line, at which it becomes very dark. Outer area variously 

 shaded and mottled with dark brown, rust color and a tinge of 

 olivaceous, though sometimes evenly composed of the ground color. 

 One or two usually minute submarginal white spots are between 

 veins \{. to Cuj and a black spot also is occasionally present between 

 the two branches of cubitus. Discal spot conspicuous, white, angu- 

 lar, linear. Fringe testaceous to brown. Ground color of second- 

 aries whitish, rarely with a yellowish or testaceous cast and overlaid 

 with fuscous scales, especially along the transverse line and, to a 

 less extent, the inner margin. Transverse line brown, variously 

 waved and denticulated and followed by a conspicuous line of ground 

 color. Three or four intervenular black triangles are on the outer 

 margin near the anal an^le and occasionally there are other smaller 

 ones along the remainder of the outer margin. Discal spot absent 

 or showing as a white, linear mark. Fringe as in primaries. Beneath 

 whitish or very pale smoky with or without a yellowish or testace- 

 ous cast. Lines of above except the inner of primaries repeated, 

 that of secondaries strongly denticulate. Discal spot of fore wings 

 white, often edged on one side with black; of hind wings large, black, 

 oval. 



Type. — In collection of Dr. William Barnes. 



Habitat. — Durango, Colorado, May 24 to 30, June S to 15, July 8 to 

 15; Glenwood Springs, Colorado, June, July 8 to 15, 24 to 30; Yellow- 

 stone Park, Wyoming, July 8 to 15 — all from Doctor Barnes. 



A light-colored species with rusty-yellow or brownish shadings. 

 In one female before me (fi<;. \) on Plate 13) there is a slight tinge 

 of olivaceous in the outer area, and in other slight respects the speci- 

 men resembles morrisonata, but the rusty-brown shade at once 

 distinguishes it from that form. As in ocddentalis this species 

 has dentate antenna' in the male. The clasper of the genitalia is 

 long and narrow and constricted immediately above the thumb- 

 like projection. The scaphium hook is stout and much curved. 



PERO MARMORATUS, new species. 



Plate L3, figs. LO and II; Plate I 1. fig. I l; Plate 10, fig. 9. 



Expanse, •'!() to 34 mm. Head and thorax chocolate brown, with 

 or without a sparse scattering of yellowish scales. Abdomen some- 

 what paler, variously mottled with yellowish and light and dark 

 shades of brown, the darker shades frequently at the posterior edge 

 of the segments; anal brush of male light yellowish. Antennae pale 

 yellow below, dark brown above. A more or less pronounced whitish 

 U-shaped mark crossing the front and connecting similarly colored 

 spots at the base of the antenna'. Ground color yellowish-olivaceous 

 in the male, brownish in the female. Inner line of primaries choco- 



