MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 67 



Dr. H. S. Jewett has already (Papilio, II, pp. 38 and 144) full.v described the egg- and tlie 

 larval and pupal stages of this interesting- insect, and I have only to add some details omitted b}- 

 him. My descriptions wei"e drawn up from living specimens, supplemented liy examination of 

 the alcoholic specimens of the different stages. We have, perhaps, a no more interesting and 

 beautiful caterpillar, whether we consider its peculiar appendages, its rich and gorgeous colora- 

 tion, or its defensive habits, and the most carefully described details will not be superfluous in 

 comparing the dift'erent stages with those of its allies, Citheronia regall.-i and Eacles t'mjjeruih'.s, 

 and the allied South American forms. I am indebted to my friend, Mr. W. N. Tallant, of 

 Columbus. Ohio, for sending me a good supply of eggs from which the second or .July brood 

 of larvte hatched. The food plant is the honey locust {GlficUtnehia friacanth(i!<)^ though Doctor 

 Jewett adds Gytiuiodadm canadeiii<ii<, or Kentucky coffee-tree. 



Edd. — Flattened oval, disk like, each end alike. Length, 1.8 mm.; width. 1..5 mm. At 

 first green in color, as the embryo grows, states Jewett, the ^gg becomes biconcave and changes 

 to yellowish brown, and from thirty-six to forty -eight hours before hatching the head of the 

 larva shows through as a dark brown spot. The egg is about one-half as large as that of Eades 

 iniperiallf!^ but of the same shape. The sliell under a lens appears smooth, like parchment; 

 under a one-half inch objective the surface is seen to be ornamented with very faint polygonal 

 impressed areas, which are uuich fainter and less easy to detect than those of the eg^ of E. 

 impei'ialh. The swollen nucleus or bubble in each polygon is very indistinct. 



It is interesting to compare the sculpturing of the sjiell with that of E. ImperinUK and Cith- 

 ei'onia regalis, the former heing intermediate l)etween Adelocephala and Citheronia. In E. 

 iraperialis the shell is sculptured a little more distinctly with irregular polygonal imprints which 

 are not .so closely crowded as in Citheronia, and the median raised nucleus or bubble is pale but 

 tolerablv distinct. Length, 8 mm.; width, 2.5 mm. In the shell of the egg of C. fef/ali,'< the 

 polygonal impressed cells are easily recognized under the microscope and faintly detected under 

 a strong lens. The cell imprints are much more distinct and more crowded than in the two other 

 genera, while the median nucleus or bu})b]e is more prominent and darker; it varies in diameter 

 in different cells, being from about a third to a half as wide as the cell itself. The walls are quite 

 irregular and not always distinct. 



Zarra i^tage I. — (Described four to tive hours after hatching.) Length, 4 nun. The head is 

 large, rounded, smooth, unarmed, except with a few scattered tapering dark hairs; it is blackish 

 chestnut; it is wider than the bodv and slightly wider than the prothoracic segment, which is 

 broad and flaring in front, as in Anisota; it is rather higher than wide, and on the vertex 

 slightly bilobed, and is paler in front than behind. The terminal joint of the antenna is slightly 

 bulbous and bears, besides the tactile bristle, about three olfactory rods. 



The body is suljcylindrical, a little flattened, but not so much so as in Anisota. The protho- 

 racic segment is broad and flattened, smooth and unarmed, except with about a dozen dark small 

 hairs. On each side of the second and third thoracic segments is a subdorsal pair of remarkable 

 movable spines, nearly two-thirds as long as the body, which open and close together like great 

 arms, spreading apart, or directed forward and outward more or less constantly while walking, the 

 creature at this age being rather active; they are evidently at this period defensive or deterrent 

 organs; they are stout, thick at the base, those of each pair close together at their base; they 

 slowly taper toward the end, and are armed with 12-14 short, thick, blunt, dark spines. At the 

 end of the spine is a remarkable bulbous expansion somewhat chestnut shaped, being a little 

 flattened and subtriangular. broad at the end, from each side of which arises a small slender 

 tubercle bearing a blunt, stout, dark, rod-like spine about a third longer than the tuV)ercle. The 

 appendages themselves are dark chestnut, pale amber at base and on the outer third, but the 

 bulbous tip is dark reddish black. Those of the the third tiioracic segment are very slightly 

 shorter than the pair in front, and in each pair the outer, i. e., subdorsal spine is the shorter. 

 These horn-like appendages are flexible, especially near the end, and are sometimes bent over 

 and around, so a> to form a decided 1m)w or curve, or even a nearly complete circle. Compared 



