146 ON THE FERTILIZATION OF MEYENIA EEECTA. 



aligbts on the limb and essays to enter, in so doing the lever 

 is pushed in, so that the receptive surface of the upper lip is 

 brought down on its back, where lies a supply of pollen from ano- 

 ther flower. In this way, then, pollenization is secured. Passing 

 on, the insect releases the lever, and the stigma assumes its former 

 position. Now we have to see how, in the first place, the back of 

 the insect became charged with pollen. In going to and returning 

 from the nectar at the bottom of the flower, it would evidently 

 brush the pollen off the hairs of the anthers above, by which it has 

 been retained. This, then, is the use of the anther-hairs ; had 

 the pollen fallen to the floor of the tube, it could not have 

 been carried away. The insect now has to pass out, and again 

 the lever-lip of the stigma comes into action. Just as it effected 

 pollenization when the insect entered, so now it prevents contact 

 of the pollen of its own flower. It is easily seen that the upper 

 and receptive lip is pushed up out of the way by pressure from 

 within against the lever. 



Under the microscope, I find that the edges of the two lips 

 appear to be different ; the papillae of the receptive lip are shorter 

 than those of the lever-lip and its edge is thickened. I am in- 

 debted, however, to bright weather for a strong confirmation of the 

 mechanical views I have above expressed. I have then observed 

 that the receptive lip has been bathed with mucous while the 

 lever-lip has been quite dry ; the one has thus been shown to be 

 receptive and the other not. 



I have the support of Mr. Charles Darwin, to whom I have 

 shown the specimens, in saying that this peculiar structure so 

 far is thus apparently correctly explained. It appears to me evi- 

 dent, and perhaps admits of little doubt, though on first examini 

 tion I failed to appreciate clearly the beauty and use of the 

 peculiar mechanism in question. Even to give positive and un- 

 deniable proof is no easy matter, inasmuch as I have not been 

 able to follow the precise steps in the ingress and exit of the insect : 

 for, be it remembered, the plant is a tropical one, and the plant in 

 this country placed in a conservatory ; as a consequence it is 

 extremely inopportune and difficult successfully to notice the 

 mechanism in the act of use under natural conditions. 



I have attempted to fertilize flowers, but without success ; and 

 this result is due, no doubt, to the dark weather of winter, and 

 perhaps to a loss of vital force consequent on the artificial condi- 

 tions of cultivation. Of this view there appears confirmation in 



a- 



