• JOURNAL 



OF THE 



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Vol. XXIV. MARCH, 1916. No. 1. 



THE PHYLOGENETIC ORIGIN AND THE NATURE 



OF THE WINGS OF INSECTS ACCORDING 



TO THE PARANOTAL THEORY.^ 



By G. Crampton, 

 Amherst, Mass. 



Within the past century, various and conflicting theories concern- 

 ing the origin of the wings of insects have been proposed. In order 

 to choose one of these as a " working basis " for further investiga- 

 tion, it is necessary to subject them all to a critical examination, in 

 order to determine which of them is in accord with the greatest 

 number of known facts, or is the least open to objection — and is 

 therefore the most probable and acceptable. It is with this in view 

 that the different theories, together with the available evidence upon 

 the subject, have been brought together in the following discussion. 



The theories dealing with the origin of wings in insects, may be 

 grouped into two classes, one of them containing those theories in 

 which it is maintained that the wings are entirely new structures (or 

 organs " stti generis "), while the other group contains those theories 

 in which it is maintained that the wings were evolved from preexist- 

 ing structures. As an example of the first type, may be mentioned 

 the views of Kirby, who compares the wings of insects to the lateral 

 expansions of the flanks, strengthened by the ribs and used as gliding 

 planes, in the flying lizard Draco. Kirby appears to regard the wings 

 1 Contribution from the Entomological Laboratory of the Massachusetts 

 Agricultural College, Amherst, Mass. 



1 



