March, I9i6.] CrAMPTON : ORIGIN OF WiNGS. 15 



wings, it has been claimed that this would prove that the wings are 

 modified gills. 



The structures in question, however, are not gills at all, since, as 

 we have seen, the gills are never borne along the lateral width of 

 the abdominal terga (as the structures in question are borne), but 

 are attached by a narrow constricted region to the tergum, at different 

 locations (see Fig. 4, Plate I, and Fig. 15, Plate II). The para- 

 nota on the other hand, are always attached along the lateral width 

 of the tergal plate (as the wings are also attached) in exactly the 

 same manner as these fossil structures ! The adult of Oniscigaster 

 would have shown this much better, but Fig. 15 (Plate II) depicting 

 the condition of the immature Oniscigaster, if compared with Sfciio- 

 dictya (Fig. 8) will very clearly demonstrate that the lateral abdominal 

 appendages of the fossil insect are paranota, not gills; and if we com- 

 pare the abdominal paranota of the Phasmid (Figs. 11 and 14, 

 Plate II) with the abdominal structure of Corydaloidcs ( Plate 

 II, Fig. 12), it is at once apparent that the abdominal structures 

 of the fossil insect are not gills, but are paranota very like those of 

 the Phasmid, and are even bordered by a similar fringe. It is evi- 

 dent, therefore, that the lateral abdominal appendages of these fossil 

 insects (which are homodynamous with the wings and prothoracic 

 paranota) are not gills, but are paranota ! Since they are homo- 

 dynamous with the wings, this is a clear proof of the paranotal origin 

 of wings of insects. 



6. Comstock & Needham (1898-1899), Packard (1898), Hand- 

 lirsch (1906-1908) and others have pointed out that the tracheation 

 of the wings differs from that of the tracheal gills, and this, although 

 not in itself a strong argument against the origin of the wings from 

 gills, is nevertheless a point in favor of those who would derive the 

 wings from some other source, especially when taken into considera- 

 tion with the other objections to the tracheal gill theory. 



7. In the ontogenetic development of the wings, these arise as 

 projections into which the tracheae subsequently penetrate, and in 

 many immature insects the developing wings are not penetrated by 

 the tracheae until comparatively late in their development, so that if 

 the ontogenetic sequence has any meaning, the wings must first have 

 arisen as projections (paranota) not having a respiratory function, 

 but later the tracheae grew out into them. It is possible to avoid this 



