AMERICAN LEPIDOPTERA. 181 



The largest species of the typical group of Sesia, and to which it 

 belongs. At once distinguished from S. diffinis by the greatly broader 

 band on the external margin of primaries, which is dentate on the in- 

 terspaces. The form is stouter and the head wider across the vertex 

 than in S. dif&nis. 



The discovery of this species aids our conception of the structural 

 character of the genus, and leads us to consider Haemorrhagia (of 

 which S. thysbe, Fair, is typical) as a group of subgeneric value. 

 Through Sesia buffjiloensis {Haemorrhagia huff. G. & R.) and Sesia 

 gracilis {Ilaeni. (jrac. G. & R.), S. thysbe Fahr. leads up to S. axil- 

 laris, while through Sesia fuscicaudis Walk, and S. floridensis {Ilaem. 

 florid. G. & R.) in which latter the structural peculiarities of S. thysbe 

 are exaggerated ; this species leads naturally to the scaled species of 

 Aellopos. Peculiarities of coloration characterize the two divisions 

 of the genus. Thus in Sesia the colors are usually yellow and black, 

 the body squammation is more erect and bee-like, the form is more 

 compact. In Haemorrhagia the colors are claret-red and olive, the 

 body squammation is more hairy and flattened or oppressed, and the 

 form tends to become elongate and flattened. In S. thysbe, S. fusci- 

 caudis and S. floridensis, the produced palpi, flattened body, elongated 

 abdomen, and obliquely margined primaries, are characters which con- 

 trast strongly with S. diffinis, but in S. gracilis these characters arc 

 wanting, while in its coloration and style of ornamentation and in its 

 appressed body squammation it belongs to Haemorrhagia, where we at 

 first referred it. On the other hand, S. axillaris, in the long and ob- 

 lique, though still rounded external margin of the primaries, together 

 with their wide and dentate external border, approaches Haemorrhagia. 

 which latter we can. therefore, no longer consider sufficiently distinct 

 from Sesia to be retained as a genus. 



A.S Sesia thysbe, a uniformis nob., we would record the Sesia riifi- 

 caudis of Mr. Walker. This is not Kirby's species, to judge from the 

 description of that author. This is a form of S. thysbe, occurring in 

 both sexes, in which the external border of the primaries is not den- 

 tate inwardly on the interspaces. We formerly regarded this as the 

 usual female form of S. thysbe, but with more material we correct this 

 opinion. In S. thysbe both % and $ have the external marginal 

 border of the primaries dentate on the interspaces within, 



EUPROSERPINUS G. & R. ^ 



Euproserpinus phaeton, G &. li. , , 



. Euproserpinus jjhaeton, G, & R. Syn. Cat. N. Am. Sphing. p. 30. (1865). 

 Wings entire. Head and thorax above of a peculiar greyish brown, 



TRANS. AMEK. ENT. SOC. (24) SEPTEMBER, 1868. 



