March, i9i6.] CrAMPTON : OrIGIN OF WiNGS. 3 



other appendages ; while others regard the wings as modified respira- 

 tory organs (gills or spiracles) ; and still others think that the wings 

 have developed from the lateral expansions of the tergal region (not 

 necessarily concerned with respiration) which occur in numerous 

 Arthropods. These theories may be briefly reviewed as follows. 



Among those who maintain that the wings of insects arose from 

 some preexisting structures, may be cited the views of Rathke (1834) 

 who compares the foliaceous appendages which appear in the pos- 

 terior region of the cephalic lobes of the embryo of the Crustacean 

 Asellus aqiiaticiis, to a first transient indication of the wings of in- 

 sects {teste Plateau, 1871); and Cams (1839) likewise accepts this 

 view — although he also maintains that the wings have developed 

 from respiratory organs. Dohrn (1881) refers both wings and 

 tracheal gills to the " elytra" of the Annelidan ancestors of insects, 

 apparently influenced by the suggestion of Owen (1848-1855) who 

 regards the wings of insects as metamorphosed tergal branchic-e of the 

 Annelidan ancestors of insects. 



The theories dealing with the derivation of the wings from the 

 branchiae of worms, will be taken up under the discussion of the ori- 

 gin of wings from respiratory organs. It may be remarked, how- 

 ever, that those theories in which it is sought to derive the wings 

 from the gills of worms (or from the parapodial and other structures 

 of the Annelids) take a great deal for granted; and until we have a 

 wider knowledge of more intermediate forms, and their development, 

 any attempts to trace the wings, or any other Insectan structures, to 

 organs which are supposed to be their forerunners in the Annelids, 

 must be regarded as speculative in the extreme. 



Latreille (1820) compares the wings to legs; MacLeay considers 

 the wings as greatly modified limbs; Leukart (1848) thinks that 

 wings are repetitions of the legs on the dorsal surface of the body; 

 and Carus and Gerstaecker (1863) regard the wings as limbs arising 

 from the back. 



Jaworowski (1896-1897) derives the wings and legs from a com- 

 mon origin, and states that both arise as a simple hypodermal out- 

 growth within a peripodial depression corresponding to the " lung- 

 like " structure from which he derives the limbs of all Arthropods; 

 the limbs, according to him, being to all intents and purposes, modified 

 protruding respiratory lamellae. Jaworowski's theory would thus 



