77 6 



INDEX. 



Will on gastrulation, 240 



on median elements of ganglia, 

 481 



on sense of taste, 630 



on sexual cells in Aphis, 251 

 Willis, views of, 99 

 Wing, development of, 20, 161 



discs in larva, 84 

 in nymph, 320 



extension of, 163, 202 



homology of, 160 



morphology of, 160, 163 



movements of, 163 



muscles of, 220, 283 



nervures of, 163 



organs, 620 



passive rotation of, 208 



posterior muscles of, 221 



rudiments of, in larva, 84 



structure of, 162 



sclerites of, 199 



typical form of, 162 



vibration, 203 



See also Flight 

 Winter Flies, 6 



Wistinghausen on tracheal capil- 

 laries, 47 



Witlaczil on development of utero- 

 vaginal tube, 703 



Wright on Anthony's suckers, 394 



XIPHIDIUM, development of nervous 



system in, 480 

 Xylocopa, maxilla of, 133 



YELK glands of Trematodes, 708 



segmentation, 13, 232, 237 



spherules, 13 



structure of, 683 

 Yellow bodies of retina, 524 

 Yung on brain of Arthropods, 442 



on reflex acts in Crustacea, 475 



Zaddach on number of primitive 



ganglia, 65 



on origin of blastoderm, 234 

 Zoea stage of Oustacea, 30 

 /.onu radiata of germ ova, 719 

 Xopfgraten, 29 

 Zungenbein, 44 



