NO. 1140. NORTH AMERICAN NOCTUIDAE—SMI VH AND DYAB. 6 I 



becomes dull brown, tinged with green, and tlie liair olivaceous black- 

 ish, shading to yellow at the tips. 



Cocoon. — Very slight, consisting of a few threads only. 



Pupa. — llegularly tapering, the anterior sides of the segments punc- 

 tured; shining, mahogany brown, cremaster blunt, wnnkly, sHghtly 

 bilobed, contracted at base, and with a series of recurved hooks, tlie 

 upper row a single hook or absent, the lower of four or five on each 

 side; length, 19 mm.; width, G mm. 



Food plants. — Poplar, willow, birch. 



ACRONYCTA POPULI Riley. 



(Plates VII, fig. 25, larva; XT, fig. 7, female atlult; XVII, iig. 16, leg; XIX, fig. 20, male 



genitalia.) 



Acromjcta populi Riley, Second Kept. Ins. Mo., 1870, p. 119, figs. 87, 88. — Gkote, 

 Trans. Am. P'lit. Soc, 1872, IV, p. 28 = 16}) iisculina. — Riley, Index and Snpplt. 

 to Mo. Repts., 1881, p. 74, ? lepiiacidiiia. 



Aimtela populi Packard, Ins. luj. Forest Trees, 1881, p. 116, fig. 55. — Gkotk, 

 I'apilio, 1881, I, p. 127 =: lejxisnilhia. —Hknry Edwards, Ent. Amer., 1888, 

 III, p. 185, sp. dist. ; Bull. U. S. Nat. Mus., No. 35, 1889, p. 81, an sp. dist. 

 lepuHcitiina. 



Megncromicta populi Grote, Mitfcb. a. d. Roeui. Mus., Ilildesh, No. 3, 1896, p. 6. 



Ground color white, with very fine black powderings that are quite 

 evenly distributed. Head and thorax without definite markings, save 

 that sometimes there is a blackish shade across the collar, and the sides 

 of the palpi are, as usual, black. The primaries with all the markings 

 broken. The basal line is marked by a black costal spot, usually by an 

 angulated mark below the median cell, and sometin)es by a black spot 

 at just about the middle of the inner margin. The median shade is 

 marked by (piite a prominent black spot on the costa, but rarely 

 extends beyond that i)oint and never extends beyond the reniform. 

 The transverse posterior line is most nearly complete, but never con- 

 tinuous, so far as my specimens show. At its best it is somewhat lunu- 

 lated, only a little sinuate, more emphasized opposite the cell and the 

 anal angle. When least marked there is only a black spot or two opi)o- 

 site cell, and a black lunule opposite the anal angle. There is every 

 possible iutergrade between these two forms. Opposite the cell there is 

 usually an indication of a short, black streak from the transverse pos- 

 terior line, and opposite the anal angle there is a similar indication 

 emphasized by a blackish shading. In rare instances this black mark 

 extends across the line inwardly. The terminal space is a little darker 

 than the rest of the wing. There is a series of black terminal dots, 

 beyond which the fringes are cut with black. There is a short black 

 basal streak which does not extend to the transverse anterior line, and 

 does not connect with the angular mark which represents that line in 

 most of the specimens. The orbicular is wanting, or is at most very 

 faintly indicated. In one specimen only of all those before me is it 

 outlined in black. The reniform is a vaguely defined, blackish, lunate 



