THE SPHINGO-MICROPTERYGIDES. 125 



Saturniid and Smerinthid characters. Even Packard recognises in his 

 account of the larva of Sphinyicampa bicolor, the probable soundness of 

 Poulton's views, for he says of the larva of this species : "It is the 

 most Sphinx-like of any Ceratocampid (or other Bombycid) larva I 

 know, resembling Sphingid caterpillars in the following characters : 



1. The shape of the head and its markings. 



2. The four thoracic horns like those of Ceratomia, perhaps a case of 



reversion in the latter. 

 3. The caudal horn. 

 4. The large, square, heavy anal legs. 

 5. The skin granulated with small white tubercles. 



One can, when we take into account the larvae alone, well imagine 

 that the Sphingids are, as claimed by Poulton, descended from the 

 Ceratocampidae, though these may be only adaptive characters, and not 

 applicable to the imagines, which differ in neuration, in the tongue, 

 and in the proportion of the head-pieces." The characters furnished 

 by the eggs and pupae strongly support those obtained from the larva, 

 and the modification of the tongue, so strongly developed in some 

 Sphingids (e.g., Sphinx), varies much within the superfamily itself, 

 e.g., compare Smerinthus populi with Sphinx convolvuli. The evolution 

 of the tongue in Sphinx, and the higher Sphingid genera, is, neverthe- 

 less, very difficult of explanation in a stirps in which all (?) the super- 

 families are characterised by weak or aborted tongues, and where this 

 feature is even carried into the superfamily SPHINGIDES itself. Even 

 the Anthrocerids, although flower-suckers, have a very poor proboscis. 

 In discussing the evolution of the various superfamilies, it is com- 

 mon to find authors attempting to trace the origin of a superfamily 

 from an existent genus of another superfamily. This method of at- 

 tempting to derive directly one superfamily from any existent form, 

 appears to us to be a great mistake, for, as a rule, all that can be said 

 is that two superfamilies (and the same reasoning is applicable to 

 families, subfamilies, tribes and genera) have certain characters in 

 common, and, therefore, both were derived from an ancestor presenting 

 these common features. On this ground it is possible to assert that 

 Endromids, Saturniids and Sphingids, were derived from a common 

 ancestor far back in the history of the evolution of the race. Since 

 the Endromid larva is the most generalised of these at the present time, 

 it is possible to assume that the ancestor possessed more of the present 

 Endromid characters than it did of those characters now possessed by the 

 others, but considering that the existent Endromids and Saturniids are all 

 highly specialised forms, and that both superfamilies have been subjected 

 during recent geological times to similar influences to those that have 

 accompanied the specialisation of the Sphingids, it appears to us to be 

 going too far, to derive the Sphingids either through Ceratocampa, 

 Endromis, or any other existent genus. The most that can be done 

 is to derive it from Ceratocampid-like or Endromid-like (with a large 

 margin for the " like ") ancestors. 



The Sphingids form a very large superfamily, the more specialised 

 forms, with their peculiar swift, powerful flight, being eminently fitted 

 for successful competition in the struggle for existence, and also to ob- 

 tain an almost cosmopolitan range in their distribution. 



* " Life Histories of certain Moths of the families Ceratocampidae, Hemileu- 

 cidae, etc.," Proc. Amcr. Phil. Soc., 1893, p. 156. 



