MEiMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 101 



of tlic two on the eiglitli .sugiiiont, iiiitl ;inaeci with white .spiiuile.s. The suiaiKil [lUite lihieiv; it 

 is rounded with six l)laelv and several wiiite spines, the basal black ones the largest. The skin is 

 of a peculiar blackish pitchy color, ,'^piracics black, with a narrow white line around them. 

 The thoracic and abdominal legs arc dark pitchy, the latter sometimes very dark red with a sur- 

 plantar black patch; sides of the anal legs reddish, like the suranal plate; in other larva? the anal 

 legs are entirely black. S<> siilKlormI or latend j>i)il-ixh sfrlpc, lil-e those in A. inrginien-sis. 



One observed just molting from stage III, Brunswick, Me., July 27; a few minutes after 

 exuviation the body was still of the same dull chestiuit red as in stage III (though the white gran- 

 ulations show that it is in stage IV). One (the left) horn is shorter tiiaii the others. The sitines 

 are now all pale livid, as also the suranal plate and the anal legs. The thoracic and mid-abdom- 

 inal legs are pale testaceous. In one hour it became dark and the spines black. Five more 

 larvffi had molted by July 31. (Compare PI. L, 2c, 'id; LI, tig. 2c,' LII, tig. 3c.) 



Stage Y. — Length, 35 mm.; of the second thoracic dorsal spines, 0.5 mm. The head is of 

 the same cherry red color as in the previous stage. The second thoracic spine is about as long 

 as the body is thick and recurved; the other spines are moi'e curved backward and downward 

 than in the previous stage and their shape is ver}' diiierent, the upper surface being smooth, the 

 spinules being collected on the under side; the usually single large spine being white and beyond 

 the middle, with sniallci' aliortive spinules on the side; these spinules are larger on the spines of 

 the eighth and nintii segments. Suranal plate reddish, its surface rough, with white piliferous 

 granulations; near the base is a large black spine on each side, and two black ones of about the 

 same size at the end, forming a fork; the entire tentli abdominal segment reddish. Spiracles 

 black; a faint dusk}-, spiracular line. Thoracic and abdominal legs pitchy black; sides of the 

 anal legs reddish. Skin dark, with more numerous white granulations than in the previous stage. 



It is quite different and easily distinguished from A. virginiensifi; compared with this 

 species, the head is of the same size, but the color quite different, being dtdl cherry or Indian 

 ?W, while that of A. virginiensis is yellowish amber and usuallj' green. All the spines are much 

 longer; those on the back of the second thoracic longer, and those behind two or three times 

 loiiger; tlaif on the ninth ahdominal eertninJy three times a>< long as in A. virginiensis. The skin 

 is blacker, and thus the granulations are more distinct, besides being larger, while A. stigma 

 lacks the distinct suhdorsal and lateral //ink or flesh -colored hands present in A. virginiensis. The 

 spines on the suranal plate are stouter and longer. 



Stage.YI. — Some specimens reared at Brunswick, Me., again molted July 30-31. The 

 following description was drawn up August 1: 



Length, 37 mm.; width of head, -1:.5 mm. It differs from tiiose in stage V in the bod}' l)eing 

 dark, dusky chestnut and densely covered with porcelain-white granulations of uneven size. 

 There is no lateral paler line such as is seen in the previous stage. 



The horns are now less spiny, and all the horns and spines are shorter than in stage V. The 

 spiracles are larger and with an outer white ring. The head, thoracic legs, and tenth abdominal 

 segment are reddish or pale chestnut. 



Two were ol^served moving their heads from one side to the other on being disturbed. 



The following notes by Eile}^ are added from my Forest Insects, page 126: 



" Young larva. — August 24. 1870, found a lot of caterpillars feeding on Querctis bicolorf 

 They are 0.63 of an inch in length, and of a dark greenish-gra}^ color, with a broad dorsal line a 

 .shade darker; on each segment there arc six black thorns tipped with white; two on the dorsal 

 line, one on each side, and one on the margin of each side; those on the sides are very small and 

 more like tubercles; thorns on the Ijack and sides nearly equal in length, getting a little longer 

 on the last segments; on the second segment are two very long horns, resembling very much 

 antennic. the point of which is divided into two; they are directed forward and curved a little 

 backward. Head brick-red, not very glossy; feet black. Destroyed by parasites. (Rilej-'s 

 unpublished notes.) 



^^ Full grown larva. — Average length 50 mm. (xeneral color pale tawny-red, inclining to 

 orange. The whole surface covered with ))right yellow, almost white papiihe of different sizes, 

 giving a speckled appearance; the usual medio-dorsal narrow line; a broad subdorsal longitudi- 



