1893.] ^^^ [Packard. 



6. The spiracles minute and difficult to detect, as they are situated in 

 one of the transverse black bands. 



B. Evolution of Later Adaptational Characters. 



1. The forks of the larger dorsal spines disappear at the end of Stage III. 

 3. The dorsal thoracic spines become recurved in Stage III. 



3. The dorsal thoracic and caudal horn become much shorter and stouter 

 in Stage IV, when the characters of Stage V (and last) are nearly as- 

 sumed. 



4. In Stage II the dorsal spines on the prothoracic segment begin to 

 grow shorter and stouter. 



5. In Stage II the large horns begin to be less deeply forked. 



6. The transverse black stripes disappear at the end of Stage II. 



7. The dorsal and lateral spines on abdominal segments 1-7 are much 

 smaller in proportion in Stage III than in Stage II. 



8. Towards the end of Stage III the colors of the body become more 

 conspicuous and variable. 



9. In Stage III the spiracles become particolored and very conspicuous. 



10. The dorsal thoracic and the "caudal horn" become much shorter 

 in Stage IV, and not forked at the tip. 



11. The hairs become long and abundant in Stage IV. 



12. The body in Stage IV becomes much stouter and heavier than be- 

 fore, while the head has not greatly gained in size proportionately. 



Life History of Citheronia regalis (Fabr.). 



For the eggs I am indebted to Miss Morton, who sent them June 25 

 from New Windsor, N. Y. They hatched July 11. The eggs being in- 

 distinguishable in size, shape and color from those of E. imperialis, the 

 reader is referred for a description to those of the latter insect. The egg- 

 shell is so transparent that just before the larva hatches it can be seen 

 lying curved up on its side. The head is large and black, while the body 

 is pale, with distinct yellow sutures. Also the black thoracic legs are 

 visible, and the black spots, those on tiie thoracic segments, elongated ; 

 also the dark spines and certain large ochreous patches on the thoracic 

 segments. 



Larva, Stage I. — Length, 6 mm. The head is large, wider than the 

 body, smooth and shining black all over, with a few fine dark hairs. The 

 body is cylindrical, black all over, with no stripes or spots of a lighter 

 hue. A pair of large, long dorsal horns on the first thoracic segment, 

 ending in a peculiar bulbous swelling, and on each side of the segment is 

 a smaller subdorsal spine one-third as long as the dorsal ones, which is 

 simple at the end, tapering to a point, bearing a short tine near the middle, 

 and ending in a stout bristle. On each of the second and third thoracic 

 segments is a pair of dorsal horns on each side, or four to each segment. 

 The outer or subdorsal horns are only a little more than half as long as 



