21 



species with secondary sexual characters in the shape of long hair on 

 the hind wings of the & {strcchcri, smitlii, iudccisa?). We do not 

 consider that any of these groups has generic value ; the whole family 

 seems to us rather to form a chain of gradual development from a 

 primitive roughly haired ancestor with no secondary sexual characters 

 nor specialization of venation to forms possessing one or both of these 

 features. 



Dyar and Skinner have both given tables by which to separate the 

 species found in the United States ; Dyar has confused cofaqui with 

 a form of strcckcri which we describe later; Skinner's identifications 

 appear to be correct but the key is not very lucid ; section 22 refers to 

 yuccac S ; 26 evidently to yiiccac 9 ; section 24 is very confused, in- 

 cluding 3 subheads, the last of which has no reference to the preced- 

 ing and could well have been omitted as far as we can see. Both 

 authors omit sniitlii. 



The genus may be shortly summed up as follows : 



Head moderate ; eyes large, prominent ; antennae set wide apart, with hair 

 pencil at base, scaled, club either long, cylindrical, or stout and slightly flattened, 

 apex neither drawn out to a hook nor prominent point; palpi stout, appressed, 

 upturned, 3rd joint minute, bluntly rounded at apex, whole palpus clothed thickly 

 with flat scales intermingled somewhat with hair ; squammation of body and 

 thora.x either rough, or smooth, appressed ; tibiae spined, fore tibiae with small 

 epiphysis, mid and hind tibiae with an apical pair of spurs ; tarsi strongly 

 spined; first tarsal joint equal to length of remaining joints; pulvillus minute, 

 conical ; venation as in preceding genus, vein Cui of primaries in $ sex bent 

 downwards at base and approaching Cib; secondary sexual characters, consist- 

 ing of long hair on secondaries, may or may not be present. 



Group I 



Thorax and base of secondaries thickly clothed with rather rough hair and 

 hair-like scales. 



M. NEUMOEGENi Edw. (PI. I, Figs. 5, 6 and 7, S , Fig. 4, 9 ). 



Megathymus neumoegeni W. H. Edwards, Papilio II, 27 (1882) ; Edwards, Cat. 

 Diur. Lep. p. 80 (1884) ; Ottolengui, Ent. News, VI, 218 (1895) ; *Druce, 

 Biol. Cent. Am. II, 320, PI. 69, Fig. 4 (1896) (3 ) (nee. Fig. 3) ; Skin- 

 ner, Cat. N. Am. Rhop., p. 99 (1898) ; Strecker, Lep. Rhop. and Het. 

 Supp. Ill, 26, (1900); Dyar, Bull. U. S. Nat. Mus. 52, p. 47 (1902); 

 Mabille, Gen. Insect, Hesp. p. 185 (1904) ; *Wright, Butt. West Coast, p. 

 255, PI- XXXII, Fig. 483 ( $ nee. 9 ) ; Dyar, Jour. N. Y. Ent. Soc, 

 XIII, 141 (1905) (partim) ; Skinner, Ent. News, XVII, 112, (1906); 

 Skinner, Tr, Am. Ent. Soc, XXXVII 206 (1911). 



