1006 



the crying colours nor their queer arranpjement justifying the infe- 

 rence that they could ever be the direct consequences of the useful 

 effect they produce in favour of the animal. 



The comparison of Sm. oceUata with populi, and of both with 

 other Sphingides, leads me to the following conclusions: 



The colour-pattern of populi is more primitive than that of ocel- 

 hta, it agrees with the conditions whit-h may be posed for a pri- 

 moidial pattern, and it corresponds to the fundamental plan, as this 

 is found in Arctiïds, and most probably in numerous other families 

 of Heterocera, possibly also in Rhopalocera. It therefore is not only 

 older than the genus Suierinthiis, but eveu than the family of Sphin- 

 gides, perhaps than the entire order of Lepidoptera. So it cannot 

 without great restriction be (pialified as a generic pattern. 



The colour-design on the up|)er side of ocellata can be derived 

 from that of popnli hy the assumption, that the ribbons of interner- 

 vural spots occurring in the latter have been s|)ecially transformed 

 in the former. But each of these tiansformations in itself is seen as 

 well in otlier species of Smerinthus, and even in many other genera 

 of Sphingides, it is therefore not allowable to assume, tliat they 

 should liave been acquired during the formation of ocellata from a 

 />o/m//-like ancestor. Eacii for itself they are not characteristic of 

 ocellata, and cannot be taken as specific features of this species. It 

 is only the peculiar combination of the modifications of the ancestral 

 type with the subtle nuances by which in ocellata tliey are distin- 

 guished from the similar modifications in allied forms, that in the 

 end give the specific character to ocellata. At any rate the origin of 

 the said modifications of the primitive pattern cannot be ascribed to 

 the influence of protection against enemies, which ocellata obtains 

 by the use she (instinctively) makes of her eye-spots. The special 

 refinement however and the elaborate details, by which the pattern 

 of ocellata surpasses that of other Sphingides near akin, may well 

 be the consequence of natural selection, which could enter into 

 action as soon as by coincidence of hereditary variations of the 

 fundamental Sphingidial pattern with special circumstances of life, 

 a deceitful likeness had been established to the face of a big-eyed 

 owl, which frightened away preying little birds and small mammals. 



Groninqen, October 1918. 



