Chap. VII. MOEMODES IGNEA. 215 



to the edges of the stigmatic cayity where it is lodged, 

 ruptured, and the poUinium was shot upwards and fell 

 on the crest of the labellum as just described. 



Now let us suppose an insect to alight on the 

 folded crest of the labellum, and no other convenient 

 landing-place is afforded, and then to lean over the 

 front of the column so as to gnaw or suck the bases of 

 the petals swollen with sweet fluid. The weight and 

 movements of the insect would disturb the labellum 

 and the bent underlying summit of the column ; and 

 the latter, pressing on the hinge in the angle, would 

 cause the ejection of the poUinium, which would in- 

 fallibly strike the head of the insect and adhere to 

 it. I tried by placing my gloved finger on the summit 

 of the labellum, with the tip just projecting beyond 

 its margin, and then gently moving my, finger it was 

 really beautiful to see how instantly the poUinium 

 was projected upwards, and how accurately the viscid 

 surface of the disc struck my finger and firmly 

 adhered to it. Nevertheless, I doubt whether the 

 weight and movements of an insect would suffice to 

 thus act indirectly on the sensitive point ; but look 

 at the drawing and see how probable it is that an 

 insect leaning over would place its front legs over the 

 edge of the labellum on the summit of the anther- 

 case, and thus touch the sensitive point. The pol- 

 linium would then be ejected, and the viscid disc 

 would certainly strike and adhere to the insect's head. 



Before proceeding, it may be worth while to mention 

 some of the early trials which I made. I pricked 

 deeply the column in different parts, including the 

 stigma, and cut off the petals, and even the labellum, 

 without causing the ejection of the poUinium; this, 

 however, once happened when I cut rather roughly 

 through the thick footstalk of the labellum, the fila- 



