The Origin of the Markings of Caterpillars. 257 



those of this European species in the adult state ; 

 but in the two former the markings are of special 

 interest as indicating the manner in which the 

 primary Sphinx-marking has become transformed 

 into that of the apparently totally different adult 

 P. GEnotherce. P. Gaurce is green, with a com- 

 plicated latticed marking, which closer observation 

 shows to arise from the dorsal line being resolved 

 into small black dots, whilst the subdorsal line is 

 broken up into black, white-bordered triangles. 

 This caterpillar therefore gives fresh support to 

 the remarkable phenomenon that the animals as 

 well as the plants of North America are phyleti- 

 cally older than the European fauna and flora, a 

 view which also appeared similarly confirmed by 

 Deilephila Lineata^ the representative form of 

 D. Livornica. In entire accordance with this is 

 the fact that the larva of P. Gaiirce is without 

 the eye-spot on the eleventh segment, and instead 

 thereof still shows the original although small 

 caudal horn. The perfect insect also resembles 

 our P. (Enothera in colour and marking, but not 

 in the form of the wings. 



That the caterpillars of the genus Pterogon 

 originally possessed the caudal horn we learn 



of Butler's revision. Of the former he states : " Transforma- 

 tions described, and larva and imago figured, Am. Ent. ii. p. 

 123, 1870; the larva is also figured by Scudder in Harris's 

 'Correspondence,' PI. III., Fig. i (1*869), and by Packard in 

 his ' Guide,' p. 276, Fig. 203." R.M.] 



S 



