MR. A. G. BUTLER ON THE SPHINGID^E. 589 



22. Triptogon maackii. 



Smerinthus maackii, Bremer, Bull, del' Acad. Sci. St. Pe"tersb. ill. (1861) ; Lep. Ost-Sibirieus, p. 34. 

 no. 153, tab. iii. fig. 11 (1864). 



Ussuri. 



23. Triptogon modesta. 



Smerinthus modestus, Harris, Sill. Journ. vol. xxxvi. p. 292 (1839) ; J, Strecker, Lep. Rhop. & Het. 



part 7, p. 60, pi. vii. fig. 11 (1873). 

 Laothoe modesta, Grote, Bull. Buff. Soc. Nat. Sci. i. p. 24 (1873). 

 Smerinthus princeps, Walker, Lep. Het. viii. p. 255. no. 21 (1856). 



Canada, Lake Superior, New England, &c. {Strecker). 9 , B.M. 



This is unquestionably the proper place for this species. 



Genus 8. Laothoe, Fabricius. 

 Laothoe, Illiger's Mag. vi. p. 287 (1808). 



1. Laothoe populi. 



Sphinx populi, Linnaeus, Syst. Nat. i. 2, p. 797. no. 2 (1766). 

 Polyptychus populi, Hiibner, Verz. bek. Schmctt. p. 141. no. 1517 (1816). 

 Smerinthus populi, Godart, Hist. Nat. Lep. France, iii. p. 71, pi. 20. fig. 3. 

 Laothoe populi, Grote, Bull. Buff. Soc. Nat. Sci. i. p. 24 (1873). 



England [Brit. Coll.] ; Europe (Becker). B.M. 



I find, after a careful comparison of the Smerinthus modestus of Harris with L. populi 

 that they differ so much in structure from one another, that I cannot follow Mr. Grote 

 in placing them in the same genus. The form of the wings, the direction of the disco- 

 cellulars, and the length of the branches of the subcostal nervure, will at once distin- 

 guish them. 



I have not thought it worth while to refer to the hybrid form between this genus 

 and Smerinthus, although Mr. Strecker gives it, in his work, a distinct heading, as if it 

 were a species. 



2. Laothoe tremuljs. 



Sphinx tremulce, Treitschke, Schmctt. Eur. x. 1, p. 110 (1834). 



Smerinthus tremulce, Duponchel, Hist. Nat. Lep. France, Suppl. ii. p. 29, pi. 2. fig. 2. 



Moscow. 



