MEMOIKS OF THE NATIONAL ACADEMY OF SCIENCES. 91 



•extradiscal line not always distinct, forming an obliciuc wedjije shaped costal mark, wliich is bent 

 outward on the subcostal vein and irreji^ularly scalloped between all the venules, the sjiace 

 inclosed by these two lines foriuinij a broad obscurely luteous or clay-yellow band which is about 

 two or three times as wide on the costal as on the inner edge of the wings. This broad band is, 

 ■especially in the 9 , clouded with blackish scales toward the middle and hind edge, or in some 

 i S grayish uear the costal edge. A submarginal twice-bent line obtusely bent in tiie second 

 median intersi)ace, and again toward the apex of the wings. Fringe coiicolorous with the wings 

 and spotted with dark on the ends of the venules. 



Hind wings slightly paler than the lore wings, usually nearly as dark as the fore wings, 

 beconung darker touard and at the outer edge, sometimes with a dark cloud on the iuner angle. 

 The wings beneath uniforndy light ashen, with a distinct black costal spot on the outer tliird of 

 the fore wings, and on the hind wings just beyond the middle of the costal edge a dark blotch, 

 from which in some specimens a broad diffuse line i)asses in toward the middle of the wing. 



Length of body, <J , it to ll! mm.; 5 , 11 mm.; expanse of wings, S , L'T-oO mm.; 9 , 33 mm. 



The species will be recognized by the uuifiu-m cinereous tinge, by the three transverse lines 

 on the fore wings, by the broad clay-yellowish baud, limited within by the slight inwardly curved 

 inner or second line and externally by the scalloped extradiscal line, and by the i)lani outer half 

 of the wing, interrupted near the margin by the rather obscure twice waved darker line, and by 

 the plain hind wings. 



My original type, formerly in the museum of the Peabot'v Academy of Science, Salem, is now 

 in my own collection. 



Having obtained a colored drawing of Walker's type in the British Museum (I'l. ^'II, tig. 1), 

 there seems no reasonable doubt but that his name has i)riority. 



E<i(/. — Hemispherical in shape, though unusually low, shell smooth, shining greenish when 

 fresh or the embryo is within, as the shell is unusually thin and transparent. Under a Tolles 

 trii)let the shell is seen to be very minutely pitted; under a half inch objective the shell is seen to 

 be ornamented with closely crowded, convex swellings or blebs, with a distinct swollen or thickened 

 liexagonal edge and a moderately sized central boss or low papilla. The egg is unusually small 

 compared with those of other Notodontiaiis, especially those of Pheosia dimidiata, being only half 

 as large. Diameter, mm. They are laid singly on the underside of the leaf of the aspen, and 

 from their greenish color and small size are difticult to detect. The larva emerges from the egg 

 through a bean-shaped hole on one side of the egg, as lu Pheosia. 



Larva, Stage I. — Length when tirst hatched, before feeding, 2.5 to 3 mm.; length when 

 ■described, soon after hatching, 4: mm. Head round, smooth, large, or twice wider than the body; 

 pale whitish green, nearly of the color of the body, which is whitish green, with no stripes, spots, 

 or markings of any kind; the body long and slender, rather tiattened, with the sutures deeply 

 impressed, the segments being unusually convex, but entii'ely smooth, not wrinkled. The 

 glandular hairs (PI. YIII. fig. .">) are very short, minute, moderately thick, and slightly swollen at 

 the end, wliich is divided into three rather slender processes or fork.s. Body tapering to the end, 

 which is not uplifted; in fact, the attitude of the young larva is singular, the body being curved 

 laterally so that the head nearly touches the tail. The larva feeds on the underside of the leaf. 



The eggs and young larva were found July 2, on Ilirch Island, Casco Bay, ^Maiiie; some 

 freshly hatched larva; also occurred July G. 



They had already spun on the underside of the leaf a roundish, white mat of silk, on which 

 the caterpillar rested preparatory to exuviation. 



When 7 mm. in length just before molting (July 4) the head is still much wider than the 

 body, and now there are two faint dark dots on the head (on the vertex) and two subdorsal .sTraw- 

 yellow lines extending from the front edge of the prothoracic segment to the suranal xilate. The 

 sutures are also yellow. The body tapers from the prothoracic segment to the end. 



One molted July 5, and is described as follows: 



Larva, Stage II. — I/ength at first, 7 mm; differs from Stage I in the two conspicuous black 

 di\iding short bands on the heail, ending above the eyes. The two yellow subdorsal lines and 

 the transverse linear bars formed by the yellow s.utures are as at the end of Stage I. The body 

 is still rather tiattened. The glandular hairs are retained in this stage, and are very short and of 

 the same shape as in Stage I. 



