NORTH AMERICAN LEPIDOPTERA. 343 



exserted over reuiform ; a black longitudiDal line at base, reachiug into the 

 elongate narrow orbicular, which almost crosses the median space, and is dis- 

 tinctly black ringed. It is whitish, with a central dusky line. Orbicular 

 elongate, confluent with the somewhat triangular reniforni ; the combined spot 

 is black margined, then white ringed, the centre a trifle paler than the ground 

 color. Through the subterminal space is an oblique, diff'use, pale shade. T. p. 

 line white, interrupted, strongly dentate, preceded by a series of sagittate black 

 dashes, which are narrowly and somewhat indefinitely pale margined; a row of 

 terminal black lunules. Fringes pale, cut with fuscous, and with a central line 

 of same color. Secondaries white at base, with a more or less visible discal 

 lunule and a distinct, broad, blackish outer margin. Fringes white. Beneath 

 white, powdery, with broad black margins on all wings. Collar with a basal and 

 terminal blackisli line ; thorax black powdered. Expands 1.25 — 1.35 inches ; 

 31—34 mm. 



Hab. — Colorado, Nevada. 



A very distinctly marked species, readily recognizable by the con- 

 fluent ordinary spots and the dark and light contrasting maculation. 

 The genitalia are somewhat ])eculiar ; the harpes are normal with a 

 rounded oblique tip inwardly fringed with small spinules. The 

 clasper is broad, very decidedly concave and dilated at middle, and 

 as abruptly narrowed to an acute tip ; very different from all other 

 species in that respect. 



O. riparia Morr., Can. Ent. 1875, vii, 213, Oncocnemis,vdY. chandleri : Grt , 

 Bull. Surv. iii, 117, var. chandleri ; Can. Ent. 1880, xii, 256 = chandleri ; Bull. 

 Bnfi". Soc. N. Sci. 1876, iii, 87 = chandleri ; Stett. Ent. Zeit. 1876, v, 37. 117 = 

 chandleri; Pap. 1880, i, 34, an. sp. dist. ?; Tepper, Bull. Bkln. Ent. Soc. 1879. 

 i, 31 (locality and habits). 



Head, tliorax and primaries very pale luteous gray. Primaries with the ordi- 

 nary lines lost or but faintly marked on costa. A longitudinal black line from 

 base terminating in the long narrow claviform which is white marked and nar- 

 rowly defined by black scales. Orbicular very long, with very narrow defining 

 ring of black scales, a well marked white ring and a central concolorous line, 

 sometimes also marked with black scales. Usually this spot is well separated 

 from the reniform, rarely it touches it, and in no specimen seen by me do the 

 spots become confluent as in chandleri, though this may happen. Eeniform mod- 

 erate in size, hardly defined, white marked superiorly. S. t. line a more or less 

 interrupted series of white spots, preceded by sagittate black or fuscous spots, 

 which are usually edged with indefinite white shades. This is very variably 

 distinct, one specimen lacking all but a single white margined spot, wliile another 

 has an almost continuous line. No distinct terminal lunules. The costal region 

 is usually powdered with white, and there is sometimes a whitish shade through 

 the s. t. f^pace. Secondaries white, with a variably distinct dusky outer border, 

 the entire wing sometimes becoming smoky. Beneath white powdery, primaries 

 a little smoky outwardly and on disc, secondaries with a discal lunule. Collar 

 whitish, with luteous graj' tips, and less distinct basal line. Expands 1.30 — 1.50 

 inches; 33 — 37 mm. 



