142 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



middle dorsal ones are a little larger. The ''penultimate .seg-ment" (eighth abdominal one) has a 

 jiigh median dorsal spine, and two on each side, tlie last segment having only tour spines. In 

 fact, the larva is represented as being closely similar to that of C. regctlis, ditiering chief!}' in the 

 spines being bristly rather than spiny. 



Larva. — (PL LV, tig. 3.) AVhat appears to be the larva of this species is represented hy 

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

 from Mondez, Brazil (Thayer Expedition), and one from Macacos, Brazil (Roberts). 



Length, TM mm. Compared with the blown larva of C. laocoon (C. ixloii) in the U. S. 

 National Museum, it diflers in the following respects: 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 base, subconical. and the spinules on it are more prominent and more 

 crowded. 



The dorsal spines on abdominal segments 1-7 are of the same size and shape, there being 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 prominent. (For 

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



Burmeister states that the anterior spines of C. ixion {C. laocoon) 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 ai'e most probably the larva 

 of C. pli.oronea, rather than of C. principalis, the other Brazilian species. 



His figure 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^/v'i/ia 

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



Gt'ograj}hicaJ distvihution. — 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 C. aroa is from Aroa, Venezuela. Druce gives as the habitat Honduras and 

 Venezuela (Aroa). 



ClTHERON'I.'V Xj^OCOON (Ciainer). 



Pis. XVIII, fig. 1 J' , XIX, fig. 99. 



Phalxna Attacus laocoon Cramer, Papillons Exot., II, p. 30. PL cxvii, fig. A. 1779. 

 Ci(/i«WHa cmo.ssa Hi'EBNER, Verz. Schinett. p. 1.53. No. 1600. 1818-1822. 

 Eacles princeps Walker. Cat. Lep. Het. Br. IMus. VI, p. 1374, 18.5.5. 

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

 Ceratocanipa ixion Boisduval, Annales Soc. Ent. France (4), VIII, p. 31.5. 1868. 

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



Larva. 



Pis. XVI, fig. 2, LV, fig. 2. 



Biirmchtcr, Descr. phys. R^p. .\rgentine, Lepidopteres. Atlas. PI. xix, fig. 2. 1879-80. 



InuKjo. — 1 $ . Body and wings of the .shape of S C. rcgalis and mexicana. Ground color 

 grayish orange, as in C. regalis. Antennae as in O. regaUs. 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 maxillas are separate, extending beyond the palpi, being a little longer 



