LEE BARKER WALTON 15 



ology, with the possibih'ty of paleontological^ evidence 

 affording some help in the solution of the problem. The 

 ratio of development between wing and pterygodum on 

 the other thoracic segments allows the inference, how- 

 ever, that pterygoda may exist in front of the patagia 

 which then have the value of wings. 



Another interesting question in this connection is the 

 homology of the elytra of Coleoptera, for again further 

 investigation must be awaited before a logical conclusion 

 can be reached. The tracheation of the elytra, to which 

 attention has been called by Comstock and Needham 

 ('98), is not conclusive evidence that they are specialized 

 wings, for in connection with the view I have here ad- 

 vocated this would be expected if they were homologous 

 with the mesothoracic pterygoda of the Lepidoptera, and 

 the suppressed wing was represented by the alulet so 

 noticeable under the Elytra in Hydrophilus, etc. 



From the preceding facts, to which I have called atten- 

 tion, it appears necesssary to consider that the typical 

 thoracic segment possesses the components of both ptery- 

 godum and wing, the former joined to the dorsal margin 

 of the episternum, the latter articulated with the dorsal 

 margin of the epimeron, while furthermore the morpho- 

 logical position of the pterygodum in respect to the wing 

 indicates that it may have an important bearing in eluci- 

 dating the metamerism of the antennate arthropods. 



BIBLIOGRAPHY 



24 AuDOUiN, V. Recherches anatomiques sur le thorax des animaux articules et 



celui des insectes hexapodes en particular. Ann. Sci. Nat. Zool. Tome i, 



p. 416. 

 '86 Cholodkowsky. Zur Morphologie der Insectenflugel. Zool. Anz. Bd. ix, 



p. 165. 

 '87 Cholodkowsky. Ueber die Prothoracalanhange bei den Lepidopteren. Zoo/. 



Anz. Bd. X, p. 102. 



The prothoracic appendages of certain fossil insects {Homoioptera woodwardi, 

 Sfenodicta lobata, Lithontantis goldenbergi, carhonaria, etc.) so excellently figured 

 by Brongiart (Recherches pour servir a I'hhtoire des insectes fossiles, Paris, 1894) 

 cannot be homologized with the expanded margin of the prothorax in existing 

 Mantids, as Woodward (Quart. Journ. Genl. Soc, vol. xxxii, p. 60, London) sug- 

 gested. Brongiart has already pointed this out. (Note sur quelques insectes fossiles 

 du terrain houiller qui presentent au prothorax des appendices aliformes. Bull. Soc. 

 Philom., tome ii, 1890.) 



