58 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.xxi. 



ACRONYCTA CRETATA, new species. 



(Plates XI, figs. 3, 4, male and feiuaU-, adult; XVII, fig. 15, leg; XIX, fig. 18, male 



genitalia. ) 



Grouud color chalky white, with a sparse powdering of black scales, 

 which are chiefly massed along the costa, the internal margin, and 

 behind the transverse posterior line. The basal line is indicated by a 

 small black dot on the costa. The transverse anterior line is marked 

 by a black si^ot on the costa, a triangnlar mark in the siibmedian inter- 

 space, and an irregular blotch on the internal margin near its middle. 

 The median shade is marked by a black spot on the costa above the 

 reniform, and it may send a vague shade to that spot. The inception 

 of the transverse jiosterior line is also marked by a black spot on the 

 costa, the line bending outwardly very strongly and then bisinuate, 

 more or less broken, to the inner margin. The line is emphasized oppo- 

 site the cell by two more or less obvious black marks which indicate a 

 dagger, and in the submedian interspace it is very prominent and 

 crossed by a distinct dash, forming a typical psi. The subterminal line 

 is wanting. There is a series of distinct black terminal dots, which 

 extend to the middle of the fringe in the interspaces. Tiie ordinary 

 spots are not well marked. The orbicular may be absent; it may be a 

 small black dot or a small circlet. The reniform is blackish or black 

 and irregularly lunate. There is a short black basal streak which does 

 not reach to the transverse anterior line. Secondaries white, the veins 

 a little smoky, and in the female a more or less obvious discal spot. 

 Beneath pure white, both wings with a discal lunule, and in the female 

 with a more or less well-marked outer line; a series of terminal spots 

 on both wings. The head and thorax are without markings, save for 

 the very prominent black line which extends from the sides of the 

 palpi across the eye and to the base of the wings. 



Expanse, male, 1.45 inches (36 mm.); female, 1.80 to 2 inches (45 to 

 50 mm.). 



Hahitat. — Garfield County, Colorado; 7,000 feet. 



Three specimens collected by Mr. Brace are types in the collections 

 of U. S. National Museum and Eutgers College. The male is numbered 

 833, the females 827, 828. Whether the difference in size between the 

 sexes is always so strongly marked as in the specimens before me I can 

 not say, but I am inclined to doubt it. The male specimen here is 

 probably undersized, and the markings are much less definite than they 

 are in the female. This species is easily distinguished from its nearest 

 ally, leporma, by its chalky white ground color and its more powdery 

 markings. The genital structures are also quite obviously distinct. 

 In cretata the harpes arc much narrower and the tip is irregularly 

 rounded, while the clasper is much shorter and stouter than in.its east- 

 ern ally. The structure of the front legs in the male is also different, 

 the femur being much the stoutest in cretata, while the tarsi are rela- 

 tively longer. 



