CONTENTS. 



Introduction Pages 1-5 



CHAPTEE I. 



OPHEB^. 



Structure of the flower of Orchis mascula — Power of movement of 

 the pollinia — Perfect adaptation of the parts in Orchis pyra- 

 midalis — Other species of Orchis and of some closely allied 

 genera — On "the insects which visit the several species, and on 

 the frequency of their visits — On the fertility and sterility of 

 various Orchids — On the secretion of nectar, and on insects 

 being purposely delayed in obtaining it 6-44 



CHAPTEE II. 



OFEBE^ — ay 



Fly and Spider Ophrys — Bee Ophrys, apparently adapted for 

 perpetual self-fertilisation, but with paradoxical contrivances for 

 intercrossing — Herminium monorchis, attachment of the pol- 

 linia to the front legs of insects — Peristylus viridis, fertilisation 

 indirectly effected by nectar secreted from three parts of the 

 labellum — Grymnadenia conopsea, and other species — Habenaria 

 or Platanthera chlorantha and bifolia, their pollinia attached to 

 the eyes of Lepidoptera — Other species of Habenaria — Bonatea 

 — Disa — Summary on the powers of movement in the pollinia 



45-79 



