142 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



middle dorsal ones are a little larger. The "• penultiiiuite segment" (eighth abdominal one) has a 

 high median dor.sal spine, and two on each side, the last segment having only four spines. In 

 fact, the larva is represented as being closely similar to that of C. regalis, diti'ering chiefly in the 

 spines being bristly rather than spiny. 



Larva. — (PI. LV, tig. 3.) What appears to l)e the larva of this species is represented by 

 certain alcoholic specimens in the Museum of Comparative Zoology at Cambridge, Mass., two 

 from ]\Iondez, Brazil (Thayer E.xpedition), and one from Macacos, Brazil (Roberts). 



Length. 7i> mm. Compared with the blown larva of C. laocoon {€'. irlvn) in the U. S. 

 National Museum, it differs in the following i-espects: The dorsal and subdorsal thoracic spines 

 are shorter, stouter, and the spinules on them are larger and much more crowded. They are 

 otherwise the same, being black at the swollen tips. The caudal horn is at least one-third shorter, 

 stouter, thicker at the liase, subconical, and the s))inules on it are more prominent and more 

 crowded. 



The dorsal spines on atidominal segments 1-7 are of the same size and shape, there l)eing no 

 essential diflerence. 



Suranal plate not so smooth and free from low spines as in C. laocoon, there being 10-11 

 tubercles or granulations on each side, and one of them being much larger than the others and 

 5-headed, though not so high as broad. 



The spines around the edges of the anal legs are also larger and more jirominent. (For 

 details of the armature, see PI. LV, tig. 3.) 



Burmeister states that the anterior spines of C. i.n'on {C. hiocooi)) are higher and the black 

 end swollen, and bristling with hairs; also that the upper lateral spines of the thin thoracic 

 rings are smaller. From this we infer that the specimens before us are most probably the larva 

 of C. phorotx'a, rather than of C. principalis, the other Brazilian species. 



His tigure of C. ixion also shows that the middle spine on the suranal plate is higher, more 

 prominent. 



Food plant. — Burmeister states that it eats the parasitic plant called by the Brazilians //'w/rt 

 de erhe, the botanical name of which he did not know. 



Geographical distrihtition. — French Guiana and Brazil (Boisduval), Rio de Janeiro (Bur- 

 meister). Burmeister says that the drawing of the larva was made by his son at Rio de Janeiro, 

 but he does not state whether it occurs in the Argentine Republic or not. Cramer states that 

 "it is not at all common" at Surinam. Drury gives Rio de Janeiro as the habitat, and Walker 

 Brazil. My specimen is from M. Donckier; it has no locality label. 



Schaus's ('. aroa is from Aroa, Venezuela. Druce gives as the habitat Honduras and 

 Venezuela (Aroa). 



ClTKERO:>fIA. LvVOCOON (Ciaiiiei). 



Pis. XVIII, fig. 1 ^ , XIX, fig. 9 9 . 



Phahniii Atiacus laocoon Cra.ver, Papillons Exot., II, p. .30. PI. cxvii, fig. A. 1779. 



C'KIieronia an<i.%m Hcebnbr, Verz. Sclimett. p. 153. No. 1600. 1818-1822. 



Eacleg princeps Walker. Cat. Lep. Het. Br. ]\Ius. VI, p. 1374, 1855. 



Ceratocampa laocoon Boisduval, Annales Soc. Ent. France (4), VIII, p. 314. 1868. 



Ceratocampa ixion 'BomDVVAL, Annales Soc. Ent. France (4), VIII, p. 315. 1868. 



atheroma laocoon Kirby, Syn. Cat. Lep. Het., I, p. 743. 1892. 



Larro. 



Pl.«. XVI, fig. 2, LV, fig. 2. 



Jiurmelster, Descr. pliys. Ki'^j). Argentine. Lepiilopteres. Atlas. PI. .\i.x, fig. 2. 1879-80. 



InuKjo. — 1 <J . Body and wings of the shajjc of S 0. regalis a.nA mexicana. Ground color 

 grayish orange, as in ('. regidis. Antenna- as in C regal i.s. Head yellow, with a distinct median 

 orange-red line on the front extending from the labrum upward, while the front in C. regalis is 

 all orange-red. The maxilhv are separate, extending beyond the palpi, being a little longer 



