228 MEMOIRS NATIONAL ACADEMY OF SCIENCES. vol. xii, 



semicircle is shorter and indistinct. The discal spot is small, irregular, one-half as large as 

 in C. angulifera (length 5 by 2£ mm.). 



The under side of the wings with the same hues as above, but decidedly brighter; basal 

 line wanting, faintly showing through from above. Discal spot of the same size as above, 

 minute, triangular, but more distinct. The markings of the wing beyond the extradiscal line 

 the same as above. The ocellus differs in the sinus made by the blue semicircular line being 

 filled in with pale brown scales concolorous with the margin of the wing. Hind wings within 

 the extradiscal chestnut brown, being of a darker and wider brown than on the upper side, 

 but the tint beyond this line is the same as above. 



Discal spot of the same irregular shape as above, though more distinct. 

 Expanse of fore wings, 81-102 mm.; length of fore wings, 44-51 mm. 



In five females from Rhode Island (H. L. Clark collection, Museum of Brown University) 

 there is considerable variation in size and color. Two of them closely approximate C. angulifera, 

 though still much less ochreous; the others are dark, being brown inside and deep red brick, 

 with a slight lilac tint on the broad shade beyond the extradiscal line. The outer edge of this 

 shade is zigzag alike in all, and the submarginal line is the same. The discal spots are smaller, 

 in one example those on the fore wings are reduced to an indistinct triangular discoloration; 

 in all the others the spots are tolerably distinct, while those on the hind wings are quite uniform 

 in size and shape. The distance between the extradiscal and basal lines does not differ materially. 

 There is considerable variation in the scallops of the extradiscal line in both pairs of wings, in 

 one 9 being much as in C. angulifera. There is some variation in the degree of falcation of the 

 fore wings. The subapical ocellus varies somewhat; in one 9 it is 3 mm. in length, in another 

 6 mm. being twice as large, while the blue semicircle is much longer and the brown scales may 

 be either absent or quite thick. 1 



[Geographical distribution. — In the records of the United States Department of Agriculture, 

 C. promethea is reported from the following places; Massachusetts (Maiden, Sudbury, West 

 Groton) ; New Hampshire (Winchester, Chester) ; New York (Albany) ; New Jersey (Holly 

 Beach, Hammerton, Vineland) ; Pennsylvania (Germantown, Pittsburgh) ; West Virginia 

 (Gerrardstown) ; Virginia (Newport News) ; Alabama (Lowndesboro) ; Arkansas (Bentonville) ; 

 Michigan (Detroit); Ohio (Toledo); Illinois (Manchester); Missouri (Cadet). Holland states 

 that it ranges from southern Canada to Florida.] "Very abundant in western Ontario, and 

 at any rate as far [east] as here (Ottawa)." (J. Fletcher, litt., 1900.) 



Life history. 



The larvae are at first gregarious, feeding side by side on the underside of the leaf. 



Egg. — Oval-cylindrical, somewhat flattened; the surface pure white, somewhat shining. 

 Under a half-inch objective the shell at first seems to be entirely smooth and shining, without 

 any markings, with neither pits nor polygonal areas, but after further observation very faint, 

 irregular, moderately large polygonal areas, with faintly raised edges or boundaries, can be 

 detected. Length 1.8, breadth 1.5 mm. 



The egg of C. angulifera is the same as C. promethea in shape and color, though mine are 

 slightly smaller, and the polygonal markings appear to be even fainter than in C. promethea. 



In the Attacinas the eggs present generic, specific, and perhaps varietal characters; this of 

 course depends on the structure of the lining of the oviduct, and it may be asked what natural 

 selection or the influence of external surroundings have to do with the differences in the shape, 

 structure, and markings of eggs. 



Larva. — Stage I. Described a few hours after hatching. Length, 5 mm. The head is 

 wider than the body in the middle, and as wide as the prothoracic segment; black, with a broad 

 transverse whitish band crossing the clypeus, including the apex and a large portion of the 

 clypeus itself, the labrum and base of the antennae pale. The thoracic tubercles, at first lemon- 



1 [Ab. caeca, nov. $. Discal marks on upper side of both pairs of wings reduced to nigrescent shades, without any pale area. New York 

 (H. Burnett). U. S. National Museum.) 



