NO. 1290 LARVjE of moths from COLORADO— DYAR. 409 



Mining' in the leaves oi Pnox/nodium carolmiamim on the prairie at 

 Golden near the foothills. A large blotch mine under the lower epi- 

 dermis, the upper side a little swollen and yellow. Finally the leaf 

 becomes brown and dead on both sides. Imago July 26. The moths 

 proved to belong to an undeseribed species, but Mr. Busck has pre- 

 pared the following description which is submitted in conjunction with 

 my note on the larva: 



GRACILARIA (DIALECTICA) PNOSMODIELLA Busck, new species. 



Antenna^ as long as fore wings, simple, dark bronzy with indistinct, narrow, white 

 annulations; basal joint without pecten, whitish. Labial palpi silvery white, some- 

 what loosely scaled beneath toward apex. Maxillary palpi distinct, porrected, 

 silvery white. Fore wings shining coppery golden with silvery white markings 

 edged with black. At basal third is an oblique white costal streak reaching down to 

 the fold, where it bends outward and is prolonged somewhat along the fold; between 

 this and the apex are three equidistant triangular, white, costal spots; the first at 

 middle of wing, the second at the beginning of the costal cilia, and the third in this 

 cilia. Opposite the intervals between these three costal spots are two dorsal, white, 

 triangular spots, and the base of the dorsal edge is white. All these white markings 

 are sharply edged by thin black lines. Dorsal cilia golden, apical cilia white, a short, 

 perpendicular black cross line. Underside of thorax silvery white; legs white with 

 broad black annulations; spurs white; posterior tibire pectinated above. Abdomen 

 shining dark purple, with broad white transverse bands on the under side; anal tuft 

 white. 



Alar expanse 8 to 9.5 mm. 



Habitat. — Colorado (Dyar). 



Food plant. — Pnosmodium carolimamim. 



Ti/pe.—'No. 6267, U.S.N.M. 



This beautiful and singularly marked species may fall in Lord Walsingham's 

 genus Dialectica ^ when the group to which it belongs has been critically worked up. 

 Dialectica is distinguished from Gracilaria by the pectinated posterior tibia?. It is 

 nearest and very similar in ornamentation to Coriscium alhinatella Chambers,^ but is 

 easily separated by the pure white palpi, l)y the first costal streak which does not 

 reach down to the white basal part of the dorsal edge, and by several smaller differ- 

 ences in ornamentation. 



GRACILARIA THERMOPSELLA Chambers. 



Larva. — Head flat, rounded, broadly bilobed at vertex, clypeus 

 triangular, reaching the vertical triangle; smoky luteous, translucent, 

 ocelli black; half retracted in joint 2. Joint 2 flattened dorsally, pro- 

 jecting at the sides, without distinct shield. Seg-ments nearly equal, 

 4 and 5 a little smaller, tapering a little behind, 13 suddenly smaller, 

 slender, divided. Body behind joint 2 nearly cylindrical, submonili- 

 form, segments dented subannulate; shining, pale greenish 3'ellow 

 without marks. Seta? nearly o])solete, a few pale ones on the sides. 

 Feet on joints T to 9 and 13 with a bundle of hooks directed backward, 

 not in a definite ellipse. Thoracic feet moderate, directed downward. 



Leaf miners in Ther7aop.us montana under the upper surface, the 



'Proc. Zool. Soc. Lond., 1897, p. 150. ^Can. Ent., IV, 1872, p. 25. 



