MEMOIIJ^ OF rilK NATIONAL ACADEMY OF SCIENCES. 57 



the clypeus, the epicraniuni and occiput l)cin<f very short and .situated behind the insertion of the 

 antonniw The surface of the clypeus or front is flat, as in all the .saturnian moths, owing to 

 the absence of a functional toni,nie; in Sy.s.sjjhinx the lower edj^e forms a knob-like protuberance. 

 The eyes rather large, globose. Antenna? of $ almost invariably bipectinated, either on the ba.sal 

 half or basal three thirds or three fourths, or to the end; witii about 18 to 25 double pairs; the 

 distal pectination.s of each joint nearly as long as the ba.sal ones, and both generally densely 

 ciliated; they are sometimes plumose. In the 9 either simple, subsimple, or with .short, distinct 

 pectinations, only a single pair to each joint. Labial palpi in general large and stout, .sometimes 

 (Ar.>enura) passing beyond the front; usually 3-jointed, sometimes 2-jointed (Eacles), or but 

 1-jointed and dithcult to distinguish from the hairs of the front and sternum. They are large 

 and Sphinx-like in Agliinte. especially in Arsenura, where the third joint, usually buried in the 

 hairs of the end of the second joint, is distinctly .seen. ^Nlaxilhe in many g-enera sufficiently 

 developed to be visible, but even then small, weak, the two halves separate, very slender, and 

 evidently not functioning, unless slightly .so in Citheronia, where the two maxilla? are united for 

 about half their length to form the tongue. In Anisota there are no recognizable vestiges of a 

 tongue. 



Body robust, spindle-shaped, or fusiform, or in general Sphinx-like; the thorax thick, and 

 the abdomen long, conical, and when the lateral claspers are large, as in Citheronia and 

 Syssphinx and certain AdelocephaUe, the dense vestiture on them forms lateral terminal tufts; 

 the abdomen is most conical in genera such as Ai-senura and Dysdiemonia. the vestiture being 

 closely cropped; in .some genera the vestiture of the thorax is long, dense, and shaggy. There 

 is rarely a prothoracic collar, one being slightly developed in Arseiuira and Dysda?monia. The 

 patagia are rarely distinctly apparent, owing to the dense, long vestiture of the thorax. 



The fore wings vary greatly in shape, in the more typical forms being in Ceratocampidre 

 sphingiform, the costa straight, the apex acute or subacute, the outer edge verv oblique, or they 

 ma^' be verv broad as in Arsenura and Dysdremonia, or closely similar in shape to those of the 

 saturnians (Nudaurelia, Gynanisa. etc.). 



The hind wings eciually vary from their normal proportions, the apex being rounded and 

 the outer edge entire, or they may be Sphinx-like, or variously angulated or tailed, as in Dysda;- 

 monia, in Urota, and Cercophana. 



Venation: There are in the fore wings invariably eleven veins present, and in the hind wings 

 eight or nine (nine invariably in the Ceratocampiua?, seven in Euda'monia), there being no vein 

 VI. It also differs from that of the .saturnians in the discal cell being invariably closed by the 

 discal veins. 



The discal cell is alwaj's closed, the cross vein, i.e., the two discal veins (anterior and poste- 

 rior, or "discocellulars") united to form a continuous line, which is either bent, more or less, 

 outward or inward, or regularly curved outward or inward, or directed obliijueh' outward 

 and inward. The discal cell is often small, in the typical members of the family (Ceratocam- 

 pinae) very small, short and narrow, and not extending to the middle of the wing, but in some 

 cases, in Poly thy sana, etc., it extends beyond the middle of the wing (along the cubital or vein 

 IV), .so that the veins beyond it may be very short. 



Hind wings, with eight veins; the first or anterior discal vein is very oblique, directed inward 

 and backward. 



J^(/g. — Those of the Ceratocampinie differ from those of the .Saturniida' in l)eing low, some- 

 what flattened, broad, elliptical, not cylindrical; the shell is thin and tough, parchment like, 

 while the sculpturing is partly obsolete. The eggs of the Agliina; and Buna?ina3 are not well 

 known. 



Larva. — in the larva after stage I, as well as in subsecjuent stages, the .setiferous tubercles 

 are solid and chitinized. forming a stout, long spine or horn (never polysetose rounded knobs or 

 button-like tubei'cles as in Saturniidie), in some cases bearing a ffne seta at the end. The suranal 

 plate is armed with bosses, or in some ca.ses with horns, with the result that the armature of the 

 family in general is more formidable than in any other group of Lepidoptera. The anal legs or 

 claspers are large, squarish, and solid. There is, with a few exceptions (Anisota), a caudal horn 



