Ghap. II. B(tNATEA SPECIOSA. 77 



together. As in Platanthera flava, there is a process 

 at the base of the labellum which compels moths to 

 .enter the flower on either side. The nectary, accord- 

 ing to Mr. Trimen and Mr. J. Mansel Weale, does not 

 contain free nectar; but the latter author believes 

 that the tissue of which it is composed tastes sweet, so 

 that moths probably penetrate it for the sake of the 

 intercellular fluid. The pollinia are of astonishing 

 length, and when removed from their cases hang down 

 merely from the weight of the pollen-masses, and if 

 attached to the head of an insect would be in a proper 

 position for adhering to the stigma. Mr. Weale has 

 likewise described some other South African species 

 of Bonatea.* These diifer from B. spedosa in having 

 their nectaries full of nectar. He found a small 

 butterfly, Pyrgus elmo, " perfectly embarrassed by the 

 number of pollinia of this Bonatea attached to its 

 sternum." But he does not specify whether the 

 sternum was naked or covered with scales. 



The South African genera Disa and Disperis are 



placed by Lindley in two sub-tribes of the Ophrese. 



The superb flowers of Bisa grandifiora have been 



described and figured by Mr. Trimen.f. The posterior 



sepal, instead of the labellum, is developed into a large 



nectary. In order that insects may reach the copiously 



stored nectar, they must insert their proboscides on 



either side of the column; and in accordance with 



'this fact the viscid discs are turned outwards in an 



1 extraordinary manner. The pollinia are crooked, and 



when removed bend downwards from their own weight, 



' so that no movement is necessary for placing themselves 



in a proper position. Considering the large supply of 



* ' Journ. Linn. Soo. Bot.' vol. t ' Jouvn. Linn. Soo. Bot.' vol, 

 X. p. 470. vii. 1863, p. 144. 



