10 MEMOIRS NATIONAL ACADEMY OF SCIENCES. vol. xu, 



[ARSENURA POLYODONTA (Jordan). 



Rhescyntis polyodonta Jordan, Nov. Zool., vol. 18, 1911, p. 134. — Mexico.] 



RHESCYNTIS Huebner. 



Rhescyntis Huebner, Verzeichniss bek. Schmett., p. 156, 1822. 

 Rhescyntis Walker, Cat. Lep. Het, Br. Mus., VI, p. 1320, 1855. 

 Rhescyntis Kirby, Syn. Cat. Lep. Het., I, p. 745, 1892. 



Imago. — Head narrow between the eyes, the sides of the front parallel, the scales close 

 and short, eyes large and full. Antenna of d" very long, composed of about 48 joints, which 

 are short, bipectinate; pectinations moderately long; only the last joint without a short branch; 

 those of the basal and distal pair very close to each other. Palpi large, extending well beyond 

 the front, directed upward; third joint not distinct. 



Fore wings very long and narrow, nearly two and one-half times as long as wide, very 

 falcate; costa much arched; apex broad, squarish, outer edge nearly twice as long as the inner. 

 Hind wings Attacus-hko in shape; outer edge full and rounded, especially toward the inner 

 angle; inner edge very long and straight. The abdomen only reaches to a little beyond the 

 basal third of the hinder edge. 



Venation much as in Arsenura and Dysdaemonia. In the fore wings vein III 1 arises as 

 in these two genera ; there is no vein III, (so far as I can ascertain) ; as in those two genera 

 vein IV 2 is detached, becoming an independent vein. In the hind wings the shape of the discal 

 cell, the length of the discal vein and their obliquity is nearly identical with that of Arsenura. 



Markings: There are no ocelli on either pair of wings, but an apical eye like black spot 

 on the fore wings. The moths of this magnificant genus have been associated with Attacus 

 and Philosamia since the days of Hubner, but in the venation, the palpi, and the narrow front 

 it is closely related to Arsenura. 



[Several species, described as Rhescyntis, are placed by Kirby in Arsenura. In the later 

 writings of Rothschild and Jordan, various species which Kirby lists as Arsenura (e. g., cham- 

 jrioni Druce, Jiercules Walker, sylla Cramer, armida Cramer) are referred back to Rhescyntis. 

 Rhescyntis as here understood is Machaerosema Rothschild. Kirby designates hippodamia 

 Cramer as the type of Rhescyntis, but Rothschild states that the type is armida Cramer, and 

 hence gives a new name to the Rhescyntis of Kirby and of the present work. Dr. Dyar informs 

 me that Hiibner's Rhescyntis included erythrinae ( = armida), cassandra, syUa, and hippodamia 

 in this order. Kirby apparently had a right to designate hippodamia as the type, and hence 

 Machaerosema is a synonym of Rhescyntis.} 



Geographical distribution. — Neogaeic, the genus ranging from the Isthmus of Panama to 



RHESCYNTIS HIPPODAMIA (Cramer). 



Plate LXXII, fig. 2. 



Phalaena- Attacus [hippodamia] Cramer, Papillons exotiques, II, p. 43, Tab. CXXVI, B. 1779. 



Phalaena- Attacus [hippodamia] Gmelin, Systema Naturse, I, 5, 2404, 468. 



Bombyx hippodamia Fabricius, Species Ins., II, 169, 11; Mantissa Ins., II, 109, 13; Entomologiae Systema, III, 1, 



413, 18. 

 Bombyx hippodamia Olivier, Encycl. ineUi. Ins., V, 28, 15. 

 Rhescyntis hippodamia Huebner, Verz. Schmett., p. 156, 1822? 

 Rhescyntis hippodamia Walker, Cat. Lep. Het. Brit. Mus., VI, p. 1322, 1855. 

 Rhescyntis hippodamia Kirby, Syn. Cat. Lep. Het., I, p. 745, 1892. 

 Rhescyntis hippodamia Rothschild, Nov. Zool., II, p. 35, 1895. 



Imago. — 1 6* . Body and wings fawn-brown, fore wings with a basal shade formed of two 

 parallel reddish brown curved lines, fading out toward the inner edge. No discal spot or 

 even discoloration. Extradiscal Line composed of four reddish brown lines arising close 

 together from near the outer edge and curving around to the middle of the costa, the four 

 lines slightly separating from each other. An apical oblique ocellus more developed and 

 specialized than in Arsenura (though the latter is a highly specialized genus) ; this oval ocellus 



