1 24 BOMBYCID.E. 



stituted it is of very great extent; but the most 

 cursory glance suffices to show that its contents are 

 far too heterogeneous to accord with the notion we 

 now form of a genus. Without a full series of spe- 

 cimens, or more accurate descriptive details than we 

 now possess, it would be impossible to make a satis- 

 factory revision of the Saturniae with a view to 

 their distribution into consistent genera. But there 

 are certain characteristic features affording a basis 

 for this distribution to which it may be worth while 

 briefly to advert. The hinder margin of the poste- 

 rior wings is either regularly rounded, produced 

 into an acute angle, or drawn out into a long nar- 

 row tail. As these distinctions are connected with 

 others of an equally important although less obvious 

 kind, they may be adopted for the establishment of 

 three primary groups. Of these the first is by far 

 the most extensive, including the great mass of the 

 species, such as S. atlas, hesperus, cecropia, &c. 

 To S. atlas and its congeners, distinguished by 

 their great size, development of the palpi, large 

 vitreous spaces on the disk of the wings, &c, we 

 would assign the name Hyalophora, * a term nearly 

 corresponding to Porte-mirroir of the French and 

 Spiegeldrager of the Dutch. The great majority of 

 the middle-sized and smaller species, in which the 

 vitreous space is supplanted by an ocelliform spot 

 (the British and continental species are examples), 

 might retain the old name Saturnia ; but even in 

 the section thus restricted, there is room for further 

 * Prom SxXoi, vitrum, and (ptgu.fero. 



