MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 125 



the tuhoivlosoii the .sidos of thi' body also boin<;- dt'cidcdly ^ihortci-. wliilr tlic iiiiul Icf^s are larger, 

 with a wider, dark, granuhited area on the outside. Tiie body is also thicker and heavier, while 

 the head is paler. 



It is noticeable that in tlii-- form, us in the Attaciiia", there is a great increase from one 

 stage to another in the size or l)ulk of the body, while the head does not increase in a correspond- 

 ing ratio. 



SUMMAUY OK TJIE CHIEF ONTOGENETIC FEATURES. 



A. — Congen ital churttctcrs. 



1. In stage I there are three pairs of very long dorsal deeply forked thoracic horns, nearly 

 half as long as the body. 



2. A similar median spine on the eighth abdominal segment, with one about half as long 

 on the ninth. 



?). The abdominal segments are transversely banded with black. 



4. The lateral spines on the abdominal segments bitid and nearly as large as the subsimple 

 dorsal ones. 



5. Body pale chestnut brown; head light reddish. 



6. The spiracles minute and difficult to detect, as they are situated in one of the transverse 

 black bands. 



B. — Evolution of later adaj>tatiimal c/ifiracter,^. 



1. The forks of the larger dorsal spines disappear at the end of sta,ge III. 



2. The dorsal thoracic spines become recurved in stage III. 



3. The dorsal thoracic and caudal horns become much shorter and stouter in stage IV, when 

 the characters of stage V (and last) arc nearly assumed. 



4. In stage II the dor.sal spines on the prothoracic segment begin to grow shorter and stouter. 



5. In stage II the large horns begin to he 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. Toward the end of stage III the colors of the body become more conspicuous and variable. 



9. In stage III the spii-acles 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 bodv in stage IV becomes much stouter and heavier than before, while the head has 

 not greatly gained in size proportionally. 



Food jjlants. — Oak, button wood, bass wood, maple, honey locust, wild cherry, sweet gum, 

 sassafras, elm, sycamore, beech, chestnut elder, horn beam, birch, alder, white pine, spruce, 

 cedar, cypress, juniper, (BeutenmiiUer). Sometimes injurious to trees, in Central Park, New 

 York (E. B. South wick). 



JTi(hit--<. — The transformations of this moth were first described by Harris, but the earlier 

 staii-es were tirst fuUv described by Mr. Lintner in his Entomological Contributions No. II. 

 Though usually feeding on the white pine in the New England States, where we have seen it in 

 the breeding cages of entomological friends, it also feeds on the oak, button wood, etc., and will 

 eat the leaves of the chestnut. It is too rare to be of any economical importance, but will always 

 attract the attention of lovers of fine, rather rare insects. The moth laj-s its eggs in the northern 

 States late in June, hatching in about a week or ten days; the lar\ a, according to Lintner, molting 

 at least four if not five times. A local name for it in Rhode Island is "custard moth." 



I have found the pupa at Cordova, Mexico, in March. Iniricd in the earth. 



Viirii-tiix: ]\Ir. Doll has kindly shown me a vai'iety of the lai'va from Brandt Lake, in the 

 Adirondacks, in which the body is green. The Adirondacks larva has longer, more prominent 



