120 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



and all within makes a lilac patch. A single discal spot, ])aler at the center: the extradiscal 

 line passes Aeiy near it; it is closely wrinkled or zigzag. The outer edge of the wing is cleai- in 

 all the specimens. 



lender side of the wings all yellow; clearer tiian al)ove, and either no lines or only faint 

 traces of the extradiscal on tht> fore wings; the other being reduced and small. A triangular 

 lilac patch on the margin. 



There is a great disparity in size, though not in markings between the two sexes, and in 

 markings it presents considerable variation. In size the Mexican female, reared in Providence, 

 K. I., from a pupa which I collected at Cordova, Mexico, in the "Tierra Caliente," exceeded 

 any United States specimen seen by me. 



Expanse of the fore wings, ^90-110 mm.; 9 155 mm. Length of a single fore wing, 

 £ J:U-5i! mm. ; ? 75 mm. Breadth of a single fore wing, S 21-30 mm. ; ? 38 nnn. Length of 

 a hind wing. S 28-35 mm.; $ 50 mm. Breadth of a hind wing, <? 22-27 nun.: 9 38 mm. 



The eggs were received from Mr. James Angus, and the larvEC hatched from them reared 

 in Maine, so that their development, owing to the cooler climate, may have been less rapid than 

 in New York, where the eggs were laid. 



li'f/g. — Length, 3 mm.; breadth, 2.<;i mm.; thickness, 2 mm. Flattened elliptical, each end 

 alike, white, with an equatorial, smooth, distinct ridge. The shell is white, the surface under a 

 high-power triplet is seen to be finely pitted, the pits being shallow and not closely crowded. 

 Under a half-inch objective the pits are seen to be shallow, and not often with a detinite raised 

 edge; often there is a boss or bead in the center. Arising from the spaces between the bosses 

 are slender, short, very minute hairs, originating from a swollen base. Under a one-fifth objec- 

 tive, as well as a one-half and a triplet, I can not distinguish between the microscopic structui-e 

 and markings of the eggs of i)iij>er!alis and regalis. 



The freshly hatched larvx. — Some were seen drawing themselves out of the shell June 3() at 

 noon. Length in a few minutes after hatching, 7-8 mm.; width of head, 1.5 mm. The tubercles 

 and spines become erect before the larva entirely deserts the shell. 



The head is large and full, smooth, shining, nearly twice as wide as the body behind the 

 middle, but the prothoracic segment is nuu-h wider than the body; the prothoi-acic segment is 

 above of the same color as, and the sui-face shines like the head. The l)ody is pale chestnut, with 

 a slight pinkish tint. All the spines ai'e, before it entirely leaves the egg, shining jet-black; the 

 five longest ones (four thoracic and one median alidominal) bearing white hairs, the end hairs on 

 all the shorter ones being black." The thoracic segments are without transverse dark stripes, 

 but on each of abdominal segments 1-7 there are three transverse, distinct, conspicuous, black 

 dorsal stripes; the first one in the front of the spines is broken, and wanting on the first abdom- 

 inal segment, but the two behind are unl>roken and extend a little below the position of the spir- 

 acles. The spiracles are hard to detect, as they are situated on an oblong or fourth transverse 

 black l)and l)etween the two lateral spiracles. The eighth and last two segments are not banded. 

 The large anal legs are edged w ith black behind. The thoracic legs are black. 



There are four spines on each side of the prothoi'acic segment, all of very unequal length: the 

 lowest one minute and l)ifid; the one in front of the spiracle stumpy and ending in five slender, 

 papilliform, piliferous tubercles. The subdorsal one is much longer and forked, while the two 

 dorsal ones are verj' long and slender, about as long as the head is broad and deeply forked, each 

 fork bearing a bristle. The two dorsal tubercles on the second and third tlwracic segments are 



" " I am always amazed at tlie difference in experiences. This morning I watched a set of E. imjierialin hateli, and 

 in every instani* the seta> of the tulierdes were white for several minutes after the larva had left the egg, except 

 those of the four tubercles over the head, which were 1 ilai-k before hatching, and could he seen through the shell clearly. 



" The rapid growth of the long "horns," after leaving the shell, was most interesting. In five minutes they were 

 of normal size, but half an hour was needed to give them the shining black color; in some cases longer. 



"After watching them I looked up this point in your pamphlet on Cenitocampidue, and saw how your experience 

 differed. Then I went liack to my remaining eggs and watched the process fi'om the moment the egg was liroken, 

 hoping to find some agreeing with yours, but none would. I had a 15-diameter magnifier, and could see clearly." — 

 Miss Caroline G. Soule in a letter. 



