20 



UNITED STATES NATIONAL MUSEUM BULLETIN 207 



and subterminal line much obscured, the latter not 

 denticulate, and followed by a rather faint reddish 

 shading, distinct only on dark unrubbed or unfaded 

 specimens. Hind wing pale smoky fuscous. Alar 

 expanse, 20-24 mm . 



Type locality: West Farms, N. Y. (type in BM). 



Food plant: Black walnut (larvae feeding in buds 

 and stems). 



Distkibution: New Hampshire, Durham; iVew York, 

 West Farms, Long Island ; Pennsylvania, New Brighton 

 (June); North Carolina, Black Mountain (June), Tryon 

 (May); Illinois, Chicago, Decatur (May), Putnam 

 County (June); Missouri, St. Louis (June). 



The sex-scaling of the male is of the same type as 

 that of angusella, differing as foUows: On forewing the 

 black costal streak is longer, extending to basal fifth of 

 costa; the upper streak on hind wing is somewhat 

 shorter, narrow at base, swelling to an oblong patch at 

 middle; the streak along lower vein of cell is broader 

 and longer, extending to the lower outer angle of cell. 



Hulst gives a description of the larva and life history 

 as supplied him by Fernald. Nothing substantial has 

 been added since then to our Imowledge of the biology 

 of the species. 



Genus Acrohasis, Species 23-40: A. latifasciella 

 to A. tumidulella 



[Male: Apical process of gnathos trifurcate; forewing with 

 raised-scale ridge; without sex scaling.] 



23. Acrobasis latifasciella Dyar 

 Figure 139 



Acrobasis latifasciella Dyar, Proc. Ent. Soc. Washington, vol. 

 10, p. 45, 1908.— Forbes, Cornell Mem. 68, p. 617, 1923.— 

 McDunnough, Check list, No. 6096, 1939. 



In color and macula tion similar to angusella Grote; 

 but without black sex-scaling on underside of male 

 wings. Alar expanse, 18-21 mm. 



Type locality: New Brighton, Pa. (type in USNM). 



Food plants: Hickory, walnut. 



Distribution: New York, Ilion (Sept.); Pennsyl- 

 vania, New Brighton (Aug.); District oj Columbia, 

 Washington; Maryland, Plummers Isl. (Aug.); Illinois, 

 Putnam County (June). 



Nothing is known of the biology except the food 

 plants. 



24. Acrobasis irrubriella Ely 

 FiGTJHB 154 



Acrobasis irrubriella Ely, Proc. Ent. Soc. Washington, vol. 10> 

 p. 161, 1908.— Forbes, Cornell Mem. 68, p. 618, 1923.— 

 McDunnough, Check list, No. 6095, 1939. 



Color and maculation similar to those of angusella 

 and latifasciella except: Thorax and basal area of fore- 

 wing showing little or no trace of reddish scaling; 

 reddish ocherous band on outer border of scale ridge 

 narrower and fainter; no reddish shading in terminal 

 area beyond subterminal line. Alar expanse, 19-21 

 mm. 



Male genitalia with apex of uncus more rounded than 



that of latifasciella — at best, a character of doubtful 

 specific value. 



Type locality: East River, Conn, (type in USNM). 



Food plant: Unknown, probably Carya (hickory or 

 walnut). 



Distribution: Connecticut, East River (July); Indi- 

 ana, Mineral Springs (Aug.). 



25. Acrobasis normella Dyar 



FlGTJRB 155 



Acrobasis normella Dyar, Proc. Ent. Soc. Washington, vol. 10, 

 p. 46, 1908.— Forbes, Cornell Mem. 68, p. 617, 1923.— 

 McDunnough, Check list, No. 6097, 1939. 



Similar to irrubriella except: Averages smaller; fore- 

 wing of a more even glossy texture ; more white dusting 

 on basal area, giving it a more decidedly pale gray ap- 

 pearance; the white dusting from outer half of costa to 

 and surroimding the discal dots also a trifle stronger. 

 Alar expanse, 17-19 mm. 



Type locality: East River, Conn, (type in USNM). 



Food plant: Presumably hickory. 



Represented in the National Collection by 15 speci- 

 mens from the type locaHty. In addition, there are 

 before me two smaller (15 mm.), darker, more suffused 

 specimens (male and female) from the Barnes collection 

 that McDunnough had identified as irrubriella. They 

 were reared from hickory (June) and are, I believe, only 

 a color form of normella. The male genitalia (fig. 155a) 

 show a stiiking departure in the assymetrical and greatly 

 reduced lateral elements of the trifurcate apical projec- 

 tion of gnathos, but apparently this is the result of a 

 deformation of the organ in this particular specimen. 



26. Acrobasis malipennella Dyar 

 Figure 156 



Acrobasis malipennella Dyar, Proc. Ent. Soc. Washington, vol. 

 10, p. 47, 1908.— Forbes, Cornell Mem. 68, p. 618, 1923.— 

 McDunnough, Check list, No. 6093, 1939. 



Similar to the species following (dyarella) in color and 

 markings except that the darker areas of forewing are 

 dark fuscous and lack the intense red suffusion charac- 

 teiistic of the latter. The structural differences noted 

 by Dyar (the broader, shorter forewing, its broader 

 cell, the close approximation of veins 2 and 3, different 

 on each forewing, and the connate condition of 4 and 5 

 and their remoteness from 3) are due to deformation. 

 The male type never matured properly and the fore- 

 wings are not fully developed. I beheve the specimen 

 is nothing but a color form of dyarella and a freak at 

 that. The male genitalia are very close, differing only 

 in the somewhat more broadly rounded apex of gnathos, 

 a difference of no specific significance in this group. It 

 is a pity Dyar ever described it and a still greater pity 

 that we cannot ignore bis name; for it will probably 

 have to replace dyarella Ely which was based on normal 

 specimens and is represented hj types in good condition. 



Type locality: East River, Conn. (Aug.; type in 

 USNM). 



Food plant: Unknown. 



Known only from the unique type. 



