4 Journal New York Entomological Society. I^^^°'- ^^iv, 



come under the discussion of the origin of wings from respiratory 

 structures, but has been taken up at this point, since he brings out 

 certain features having a bearing upon those theories in which it is 

 maintained that the wings are, to all intents and purposes, modified 

 legs.^ 



On page 183, Jaworowski, 1897, mentions that legs and wings can 

 be substituted for one another, in certain insect montrosities, and 

 cites the description by Nelson, 1889, of a Zygccna in which a wing 

 had grown in the place 'of a leg, and also cites the case of an East 

 Indian fig-insect (described by Simroth, 1891) which has segmented 

 appendages instead of wings (see also Fig. 11 of wing of Zophcnis, 

 by Brues. 1903). I have also observed that in certain Diptera, the 

 halteres may appear to be composed of three segments, but I do not 

 think that the apparently segmented condition of such highly modified 

 structures can be interpreted as the retention of a primitive condition, 

 although I would not utterly deny this possibility; and, since those 

 insects in which the wings arise as hypodernial evaginations within 

 a peripodial cavity are highly specialized forms, I am rather inclined 

 to regard this also as a secondary modification, rather than as a 

 retention of a primitive condition. 



Jaworowski (1896) although at first inclined to accept the view 

 that the wings are modified tracheal gills, finally repudiated this view, 

 upon having his attention called by Heider, to Heymons's investiga- 

 tions which demonstrated that in Sialis and Ephemera, the gill ap- 

 pendages are not homodynamous with the wings, thus disproving 

 Gegenbauer's contention that wings are developed from tracheal gills. 



From the preceding discussions, it is evident that the foregoing 

 theories may also imply or expressly include the idea of the derivation 

 of the wings from respiratory structures, in addition to the central 

 idea of the theory; so that it is impossible to divide these theories into 

 sharply defined classes, since they merge into each other through hav- 

 ing several ideas in common. The discussion of these theories, there- 

 fore, leads up to that of the theories in which it is maintained that 

 wings are modified respiratory organs. 



Among those who maintain that the wings are to be derived from 

 organs having a previous respiratory function, may be mentioned the 

 views of Plateau, 1871. Plateau's theory differs from those in which 

 it is maintained that the wings had a respiratory origin, in that he 

 regards the wings as highly modified spiracles. 



