Packard.] -^^O [March 17, 



alcoholic specimens of the different stages. We luive, perhaps, a no more 

 interesting and beautiful caterpillar, whether we consider its peculiar 

 appendages, its rich and gorgeous coloration, or its defensive habits, and 

 tlie most careful!}' described details will not be superfluous in comparing 

 the different stages with those of its allies, Citheronia regalis and Eacles 

 impcrialis, 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 whicli the second or July brood of larva? hatched. 

 The food plant is the honey locust (Gleditschia triacanthos), though Dr. 

 Jewett adds Oymnocladus canadensis, or Kentucky coffee-tree. 



Egg. — 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 

 egg 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 Eacles imperialis, but of the same shape. The shell under a lens 

 appears smooth, like parchment ; under a one-half inch objective the sur- 

 lace is seen to be ornamented with very faint polygonal impressed areas, 

 Avhich are much fainter and less easy to detect than those of the egg of E. 

 imperialis. The swollen nucleus or bubble in each pol^'gon is very 

 indistinct. 



It is interesting to compare the sculpturing of the shell with that of E. 

 imperialis and Citheronia regalis, the lormer being intermediate between 

 Sphingicampa and Citheronia. In E. imperialis 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 tolerably distinct. Length, 3 mm. ; width, 2.5 mm. In the 

 shell of the egg of C. regalis 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 bubble 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. 



Larva Stage I, — (Described four to five hours after hatching.) Length, 

 4 mm. The head is large, rounded, smooth, unarmed, except with a few 

 scattered tapering dark hairs ; it is blackish chestnut ; it is wider than 

 the body and slightly wider than the prothoracic segment, which is broad 

 and fiaring in front, as in Anisota. It is rather higher than wide, and on 

 the vertex slightly bilobed and is paler in iront than behind. The termi- 

 nal joint of the antenna is slightly bulbous and bears besides the tactile 

 bristle about three olfactory rods. 



The body is subcylindrical, a little flattened, but not so much so as in 

 Anisota. The prothoracic segment is broad and flattened, smooth and 

 unarmed, except with about a dozen dark small hairs. On each side of 

 the seccnd and third thoracic segments is a subdorsal pair of remarkar 



