NORTH AMERICAN EKPIIJOl'TERA. 201 



match specimens of «»i///;ior ill this respect. The difftirence in genital 

 structure is more marked, but I am not ready to base genera on tliis 

 character as yet. 



In the larval state the species are yet more dissimilar; that of 

 amyiitor has the peculiarly horned thorax ; those of hageni and uii- 

 dulosa are laterally marked with oblique stripes, and are distinctly 

 sphingiform, while catalpfe, has a cylindrical larva which is striped 

 and more or less spotted. 



In the imago state the species are as easily sej)arable. Aimjntor is 

 larger in size as a rule than the other species, though extremely va- 

 riable in this respect ; the head and collar are white, and this gives 

 the insect a rather peculiar appearance, different from that of the 

 other species ; the costal region of primaries is pale luteous brown, 

 while the transverse maculation, except near the outer margin is 

 obsolete. 



Undnlosa differs at once in the concolorous head and collar, the 

 uniformly gray primaries on which the transverse maculation is very 

 distinct. It is a smaller species in average expanse than amyator. 



Hageni is usually still smaller, the maculation very much as in 

 nndvlosa, while there is an olive green shade over the whole wing 

 which is distinctive. 



Catalpce is a darker, much more obscurely marked species, about 

 the size of hageni, without trace of green and with the transverse 

 markings obscure and partly obsolete. 



In synoptic form the species are separable as follows : 



Head iuid collar discolorous white. 

 Costal region pale luteous brown ; transverse maculation indistinct. 



anij'iitoi*. 



Head and collar concolorous. 

 Transverse maculation distinct. 



Primaries even gray without green lin<liiIO!i«si. 



Primaries suffused with green liSi"°Oiii. 



Transverse maculation obscured, general color grayish fuscous eatalpie. 



i". aitiyiitor Hiib., Samml. Ex. Schmett. ii. Agrius ; Wlk., C. B. M. Lep. Het. 

 viii. 251 ; G. & E , Pr. Ent. See. Phil. v. 164-190, Ceratomia ; Beth.,* Can. 

 Ent. i. 171, Ceratomia; Minot.,* Can, Ent. ii. 28; Bd.,* Sp. Gen. Het. i. 53 

 pi. 1, fig. 2, Ceratomia; Butl., Tr. Zool. Soc. Lond. ix. 621, Ceratomia; Pilate,® 

 Pap. ii. 66; Fernald,* Sphing. 24, Ceratomia: Grt., Hawk Moths 38, Cera- 

 tomia. 



quadricornis Harr.,* Sill. Journ. 36, 293, Ceratomia: Wlk., C. B. M. Lep. 

 Het. viii. 258, Ceratomia; Clem.,* Journ. Ac. N. Sci. Phil. iv. 1859, 179, Cera- 

 tomia; Morris,* Syn. 1862. 20.5, Ceratomia; Harr..* IiiJ. Ins. Flint ed. 323, fifs. 



TRANS. AMER. ENT. SOC. XV. (26) SEPTEMBER, 1888. 



