MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 151 



Hnhils. — Tlie niotli was collected at Kitterj^, Me., July 18, by Mr. E. Thaxter, aud at IMan- 

 «liester, Vt., August 3, by Mr. C. H. Roberts (as by labels in U. S. Nat. JIus., Wasbiugton), 

 Pujia ill August; motli. May, Jane, and August (Riley MS.). 



"Tlie species is doubled-brooded at Plattsburg, N. Y., siugle-brooded in the Adirondacks, 

 though a single $ emerged the same season " (Dyar). 



Food plants. — Betula (Thaxter, Can. Ent., xxiii, p. 34, Feb., 1891); Bctula luipurifera (Dyar). 



Geographical (UstribHtion. — Thus far only known to inhabit the Appalachian subprovince. 

 The Ibllowing localities are the only ones yet known to me: Orono, JVIe. (Mrs. Fernald); Kittery, 

 Me. (Thaxter); Vermont, New York (U. S. Nat. 3Ius.); New Hampshire (C. A.Walker); Catskill, 

 N. Y. (Mus. Comp. Zool.); Plattsburg, N. Y., Keens Valley, Essex Co., N. Y., (Dyar); Boston, 

 ]\Iass. (Sanborn); ^Manchester, Vt. (Roberts, U. S. Nat. Mus.); Maine, Canada, New York, North 

 Caroliiux (French) ; Plattsburg, N. Y. (Hudson) ; Fort Collins, Colo., June 21, at light (C. H. Baker). 



E(ig. — Flattened hemispherical ; shell under a hand lens appears almost smooth, but under 

 a ^ inch A eyepiece seen to be ornamented with six-sided areas, with raised, beaded edges. 

 Diameter, 0.7 mm. 



Larva, Stage I. — Just hatched. Length, 3 mm. Head large, much wider than the body, black- 

 brown, smooth, polished, with a few scattered long slender hairs. Body uniformly pale yellowish 

 green, tapering to the end, the segments transveivsely wrinkled, hairs long and dark, slender and 

 tapering. A faint darker dusty greenish i^rothoracic subcresceutiform plate. Body witli no 

 markings; no lines or spots. 



Providence, June 10. Eggs kindly given me by Mr. W. Dearden. All the eggs hatched at 

 nearly the same time and on the same day. 



The larva eats a hole out of one side, of the usual irregular kidney shape. 



Pupa, August; adults, May, July, and August; localities. New York, Vermont, and District 

 of Columbia. 



Papa. — About 19 mm. long, robust, tip truncate, very slightly tapering; a very slight and 

 blunt projection at tip scarcely noticeable; general surface shiny, somewhat rugose, aud remotelj'' 

 punctate. No processes or teeth at sutures between meso and metathorax. 



'■'■ Eyg^. — Laid singly, usually on the upjier side, near the middle of the leaf of its food plant 

 [Betula papyrifera). Rounded, somewhat flattened, about the shape of two-thirds of a spliere 

 with flat base; diameter, 1 mm.; heiglit, 0.(5 mm. Slightly shining, fine tur(iuoise-blue or more 

 rarely of a greenish lilue tint. Microscopic reticulations neatly defined, but rounded, scarcely 

 angular, becoming small and indistinct at the micropylar region. On tlie sides the reticulating 

 edges of the cells become broad, flat, almost like bands, reducing the inclosed depressions to 

 shallow pits. Found during the early part of July at Keene Valley, Essex County, N. Y. 



'■'■First larval stage. — On hatching the larva leaves the shell largely intact and takes up a 

 position at the extreme apex of the leaf, where it eats the upper epidermis and parenchyma. 

 Head cordate, entirely sliining black; widtli, 0.(i mm. Body rather bright greenish yellow, thoracic 

 feet black, cervical shield transverse, dusky. Setai fine, short, black, distinct, but without evident 

 tubercles; not glandular; 1 and 2 nearly in line, 3 above spiracle, 4 substigmatal posteriorly, 5 

 subventral anteriorly, (i absent as usual in the first stage. Feet all used; leg plates concohn-ous 

 witli the body. No anal plate. Length, about 3 mm. 



'■Second stage. — The larva eats away the substance from the midrib of tlie leaf at the apex, 

 using the midrib as a perch on which it rests. Head slightly bilobed, greenish; a smoky black 

 shade covers the side, including the ocelli, and a narrow smoky band reaches tlie apex in front of 

 the lateral angle; mouth brown; a few setie; width, about 1 mm. Body cylindrical, sniootli, feet 

 normal, all used. Thoracic feet and leg plates black, except the anal pair. Setre short and fine, 

 dark, from minute black tubercles, very inconspicuous; arrangement normal, six present. Body 

 green, witli very faintly indicated addorsal, subdorsal, lateral and superstigmatal waved whitish 

 lines. Spiracles pale. 



'^ Third stage. — Head rounded, flat before and lield out flat; leaf-green; a smoky black band 

 behind ocelli extends backward and upward to the side of the head, where it ends tapering; mouth 

 reddisli; width, 1.1! mm. Body as before, but the flue dark setaj have no tubercles. Color pale 

 leaf green ; on joints 2-3 a yellowish line edged above with red extends up from below the spiracles 



'Tho followiug notos ou the transformations are copied from Dyar. 



