184 VANDEiB. Chap. VII. 



membrane, to which the pedicel is united, with an 

 inferior cushion of great thickness, of pulpy, flocculent, 

 and viscid matter. The posterior margin is much the 

 most viscid part, and this necessarily first strikes any 

 object when the pollinium is ejected. The viscid 

 matter soon sets hard. The whole surface of the disc 

 is kept damp before ejection, by resting close against 

 the roof of the stigmatic chamber ; but in the section 

 (fig. C) it is represented, like the other parts, a little 

 separated from the roof. 



The connective membrane of the anther (a in all the 

 figures) is produced into a spike, which adheres loosely 

 to the pointed end of the column ; this pointed end 

 (/, fig. 0) is homologically the filament of the anther. 



The anther has this peculiar shape apparently for 

 the sake of leverage, so that it may be easily torn off 

 by a pull at its lower end, when the poUiniuin is 

 jerked out by the elasticity of the pedicel. 



The labellum stands at right angles to the column, 

 or hangs a little downwards ; its lateral and basal 

 lobes are turned under the middle portion, so that an 

 insect can stand only in front of the column. In the 

 middle of the labellum there is a deep cavity, bordered 

 by crests. This cavity does not secrete nectar, but its 

 walls are thick and fleshy, with a slightly sweet nutri- 

 tious taste ; and it will presently be shown that they 

 are gnawed by insects. The extremity of the left- 

 hand antenna stands immediately over the cavity, and 

 would in'falliby be touched by an insect visiting this 

 part of the labellum for any purpose. 



The antennae are the most singular organs of the 

 flower, and occur in no other genus. They form rigid, 

 curved horns, tapering to a point. They consist of a 

 narrow ribbon of membrane, with the edges curled in- 

 wards so as to touch ; each horn therefore is tubular, 



