Chap. Vt ACROPERA, AND SOME ALLIED GENERA. 169 



wliicli bears the viscid cap is often left sticking within 

 the chamber, with the pollen-masses close outside. 

 Many flowers were thus treated, and three of them 

 produced fine capsules. Mr. Scott also succeeded in 

 fertilising two flowers in the same apparently unnatural 

 manner, as he likewise did on one occasion by placing 

 a pollen-mass, moistened with the viscid matter from a 

 distinct kind of Orchis, at the mouth of the stigmatic 

 chamber. These facts lead me to suspect that an 

 insect with the extremity of its abdomen produced 

 into a sharp point alights on the flower, and then turns 

 round to gnaw the distal portion of thfe labellum. In 

 doing so it removes the poUinium, the viscid cap of 

 which adheres to the extremity of its abdomen. The 

 insect then visits another flower, by which time the 

 movement of depression will have caused the pedicel 

 to lie flat on its back ; and from occupying the same 

 position as before, the insect will be apt to insert the 

 end of its abdomen into the stigmatic chamber, and 

 the viscid cap will then be scraped off by the ledge in 

 front, and the pollen-masses will be left close outside, 

 as in the above experiments. The whole operation 

 would probably be aided by the oscillatory movement 

 of the labellum whilst gnawed by an insect. This 

 whole view is very improbable, but it is the only one, 

 as far as I can see, which explains the fertilisation of 

 the flower. 



The allied genera Gongora, Acineta, and Stanhopea 

 present nearly the same difficulty from the narrowness 

 of the entrance into the stigmatic chamber. Mr. 

 Scott tried repeatedly but in vain to force the pollen- 

 masses into the stigma of Gonc/ora atro-purpii/fea and 

 truncata ; but he readily fertilised them by cutting off 

 the clinandrum and placing pollen-masses on the now 

 exposed stigma; as he likewise did in the case of 



