PHRYXUS. 145 



Bacot points out (in litt.) that the imagines of two closely allied 

 species, one of which inhabits temperate and the other tropical districts, 

 or even two forms of the same species, may differ much in the greater 

 size of the head and the more prominent eyes in the tropical form. He 

 instances the Indian Hyles lathyrus, which Staudinger says is hardly 

 distinguishable from H. nicaea in pattern, and which has been referred by 

 himself and other authorities to Hyles enphorbiae as a variety, as having 

 much larger and more prominently situated eyes than the latter species, 

 whilst the length of head and the form of the abdomen are also noticeably 

 different. This variation amounts to a greater difference than exists 

 between say such distinct species as Hyles euphorbiae and Celerio gallii 

 from European districts. He points out that this must be largely associ- 

 ated with habit, and notes that the Sphingids fly at twilight in temperate 

 regions, whilst, in the tropics, there is no real twilight, and the tropical 

 Sphingids, therefore, must fly in the dark. To collect the necessary 

 light rays, a larger eye surface, more prominent eyes and a longer 

 head follow as a necessary consequence, whilst the large number of 

 flowering trees and tall climbing plants, with the flowers situated 

 on or above the plane of flight in tropical countries, in contradiction 

 to the low-growing plants whose flowers, below the plane of flight, 

 are so freely visited in temperate regions, may also have considerable 

 influence as regards the position of the eyes upon the head, a more 

 dorsal position being necessary in the more marked tropical forms 

 and a more ventral aspect in the temperate ones. One would also 

 suppose that greater powers of flight are required, owing to their 

 having to escape the attacks of larger and swifter bats and night- 

 flying birds, and, perhaps, also, to the absolute necessity of hovering 

 owing to the larger size of the flowers. 



Genus : Phryxus, Hiibner. 



Synonymy. — Genus: Phryxus, Hb., " Verz.," p. 137 (circ. 1822); 

 Stephens, "111. Haust.," iv., app. p. 5 (1835); Tutt, "Brit. Lep.," iii., p. 355 (1902). 

 Sphinx, Esp., " Schmett. Eur.," ii., pp. 87, 196, pi. viii., fig. 4, pi. xlvi., figs. 

 3-7 (1779); Berg., "Sphing. Larv.," p. 8 (1782); Fuess., "Archiv," vi., p. 15, 

 pi. xxxiii (1785) ; Bork., " Sys. Besch.," ii., pp. 83, 141, 179 (1789) ; Rossi, 

 "Faun. Etr.," ii., pp. 14, 359 (1794); Panz., "Faun. Ins. Germ.," ii., p. 21 

 (1794); Hb., "Eur. Schmett.," figs. 65, 112 (1796); text p. 96 (circ. 1805; ; 

 Don., "Brit. Ins.," vi., p. 59, pi. eciv., fig. 1 (1797); Schrk., "Faun. Boica," 

 ii., 1, p. 225 (1801); Haw., "Lep. Brit.," pt. 1, p. 60 (1803); Latr., "Hist. 

 Nat.," xiv., p. 132 (1805); Shaw & Nodder, " Viv. Nat.," xvii., pi. 724(1806); 

 Ochs., "Die Schmett.," ii., p. 214 (1808) ; Leach, " Edinb. Encvcl.," ix., p. 

 130 (1815); Sam., "Ent. Comp.," p. 243 (1819); Godt., "Hist." Nat.," iii., 

 p. 40, pi. xviii., fig. 1 (1822); Bdv., "Eur. Lep. Ind. Meth.," p. 33 (1829); 

 Meig , "Eur. Schmett.," ii., p. 136 (1830); Evers., "Faun. Vol g.- Ural.," p. 

 in (1844); H.-Sch., "Sys. Bearb.," ii., p. 86 (1846); Speyer, " Geog. Verb.," 

 i., pp. 320, 461 (1858); ii., p. 280 (1862); Hein., "Schmett. Deutsch.," i., p. 

 146 (1859). Phinx, Fuess., "Archiv," i., pi. iv., figs. 1-4 (1781). Deilephila, 

 [Lasp.,] "Jena. Allg. Lit. Zeit.," iv., p. 100 (1809); Ochs., "Die Schmett.," 

 iv., pp. 42, 43 (1816) ; Hb., " Franck Cat.," p. 87 (1825) ; Stphs., " Illus.," i., p. 

 126, pi. xii., fig. 1(1828); "Cat. Br. Ins.," ii., p. 32 (1829); Bdv., "Icones," 

 pi. v., figs. 3-4, pi. 77, figs. 2-^var. [circ. 1840); " Hist. Nat. Sphing.," p. 172 (1875); 

 Dup., "Hist. Nat.," supp. ii., p. 159 (1835) ; " Cat. Meth.," p. 42 (1844) ; Dune, 

 "Brit. Moths," p. 152 (1836); Wood, " Ind. Ent.," p. 16(1839); Humph, and Westd., 

 "Brit. Moths," i., p. 19 ([841); Dbldy., "List. Br. Lep.," p. 3 (1847); Hevdrch., 

 "Lep. Eur. Cat. Meth.," ed. 3, p. 19 (1851); Walk., "List," &c, viii., p. 

 164 (1856); Sta., "Man.," i., p. 94 (1857); Humph., "Gen. Brit. Moths," p. 

 10, pi. ii., fig. 5 (i860); Staud., "Cat.," ed. 1, p. 16 (1861); 2nd ed., p. 37 

 (1871); 3rd ed., p. 103 (1901); Ramb., "Cat. Lep. And.," p. 131 (1866); 

 Berce, "Faun. Franc.," ii., p. 22 (1868); Newm., "Brit. Moths," p. 9 (1869); 



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