98 



THE UNIVERSE. 



ample wings, nevertheless naturalists have discovered many 

 species of this order which are wingless. But although 

 we see some individuals of this group deprived of these 



47. Phalwna hi/emalis, male and female. 



48. Phald'iia nuda, male and female. 



organs, others exhil:)it the vestiges of them to show the 

 gradation. 



Thus, for instance, though the female of the Phakena 

 nuda is entirely deprived of wings, we find by the side of 

 it the Phalcena liijemnlh, the female of Avhich possesses 

 rudimentary ones, thus forming a transition to the other 



49. Stenopteryx of the Swallow — Stciioptervx 

 Hirv:ndiiiis. 



.50. Melopliagus of the Sheep — MeJo- 

 •phaijtiii Oris. 



species of an order, the members of which have four very 

 large wings. 



In the same manner when the order of flies or Diptera 



