270 Annals Entomological Society of America [Vol. IV, 



equilateral triangle in shape, not specially armed, acute; 

 The transverse rows of granulations on the thorax are all about 

 equal. Ocelli in normal arrangement, as in Sphinx. 



The species show very little distinctive in the way of struc- 

 ture (or for that matter in color and markings) P. (Calasym- 

 bolus) astylus may be a' little rougher, with better developed 

 seta? than the others, both on head and body, and the horn 

 seems a little better denned in S. ocellatus than the others. 



Pachysphinx {Triptogon, Mar umbo). Head wider than high, 

 with sparse granulation on the sides, nearly smooth, but a 

 little vermiculate on the face; the apex bluntly rounded. No 

 subdorsal row of granulations on the thorax but the meso- and 

 meta-thorax each have one high transverse crest. Horn soft, 

 variable in size. The three lower ocelli form a right triangle, 

 the posterior being unusually high. The labrum has an addi- 

 tional seta, on the margin; the four marginal setag that result 

 are about equally spaced. 



1. P. modesta. Body normally granulated, about as in 

 Smerinthus; horn minute, about rV in. long; thoracic crests 

 high and granular. (Fig. 7.) 



2. P. occidentalis. Body smooth, with a few raised gran- 

 ules on the last oblique line, only; horn about as long as height 

 of head. Thoracic crests rounded over and hardly distinguish- 

 able. (In the penultimate stage it is granular like P. modesta.) 

 This, as may be seen, is very different from the eastern form 

 modesta. (Bred from the egg by Mr. Brehme; Western.) 



Amorpha (A. populi of Europe) Labrum very deeply 

 notched (like Cressonia). Head decidedly higher than wide, 

 triangular, smooth on the face. Anal plate unarmed, and 

 horn, etc., as in Smerinthus. The last four oblique rows of 

 granules very distinctly extend over three segments. The 

 characters are nicely intermediate between Smerinthus and 

 Dilina, showing no special closeness to Pachysphinx. 



Dilina {Mimas). Horn sharply separated from the body and 

 down curved as in Sphinx; half longer than width of head, 

 mostly cylindrical. With a longitudinal subdorsal row of 

 granules on the thorax. Head half higher than wide, and 

 acute-triangular. Face smooth, the sides of the head sparsely 

 tuberculate. Supranaal with four raised tubercles in a rec- 

 tangle. Otherwise about as in Smerinthus. D. tiliae of Europe. 



