Table of Contents xvii 



CHAPTER XXIII PAGE 

 The Wings of the Lepidoptera 



(c) The more general features of the wings of the Lepidoptera 319 



(b) The clothing of the wings of the Lepidoptera 319 



The clothing of scales 319 



The clothing of fixed hairs 323 



(c) Methodsof specialization of the wings of the Lepidoptera 324 



(d) The primary divisions of the Lepidoptera indicated by the structure of 



the wings 325 



Suborder Jugatae 325 



Suborder Frenatae 326 



(e) The wings of the Jugatae 327 



The jugum 327 



The tracheation of the wings of pupae 327 



The venation of the wings of hepialids 328 



(/) The wings of the Frenatae 330 



The frenulum and the frenulum hook 330 



The loss of the frenulum in certain of the Frenatae 331 



The reduction of the radius of the hind wings 332 



The reduction of media to a three-branched condition 334 



The atrophy of the main stem of media 337 



The transfer of the branches of media to adjacent veins 338 



The first anal vein and the anal furrow 340 



The reduction of the anal area 340 



The anastomosis of veins 342 



The costa of the hind wings 342 



The humeral veins 343 



The splitting of the radial sector in butterflies 343 



(g) Comparison of terminologies of the wing- veins of the Lepidoptera 345 



CHAPTER XXIV 

 The Wings of the Diptera 



(a) The more general features of the wings of the Diptera 347 



(b) The methods of specialization of the wings of the Diptera 348 



Ordinal specializations 348 



The loss of vein M4 348 



Specializations within the order 350 



The costa 350 



The subcosta 350 



The radius 350 



The media 353 



The coalescence of veins M3 and Cui 353 



The coalescence of veins Cu2 and the second anal vein 355 



The reduction of the number of cells in a wing 355 



The anal veins 357 



The arculus 358 



(c) Comparison of terminologies of the wing- veins of the Diptera 358 



(d) Comparison of terminologies of the cells of the wings of Diptera 360 



