

^^.. 





H- ^^ 



%. 







^-^^ 



.<^'= 



''<? 



!'•••■'?. 







Above, the theoretical wing of a fly, 

 according to Robineaji, (pp. 13-17). There 

 are six rayons or rows of cells, indi- 

 cated by letters A, B, C, D, E, and F; in 

 ekch row there are typically four cells, 

 indicated by Greek letters alpha, beta, 

 gamma delta, 



Below, how it works out in the house- 

 fly wing. 



l'('^i.<|i'vv Ki 







«N" 



^A V 



.-.^^ 





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