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anther cap, before reaching the points of the antennae, which are 

 situated further back. In cases where the pollen is mature and 

 expelled by the displacement of the anther cap, the insect, standing 

 on the column, would, if a large one, receive the flying pollen masses 

 on the underside of the abdomen. If it is a very large insect that 

 causes the displacement of the pollen, by contact with the horns or 

 antennge, it would receive the pollen masses still further to the rear ; 

 but if a small insect effected the disruption of the pollen masses by 

 irritation of the antenna it is possible for them to fly clear from the 

 flower, and be lost, as there is plenty of room between the anther 

 bed and the points of the antennte for an insect to effect disruption 

 without receiving upon its body the " viscid gland." If the gland is 

 fixed upon the underside of the insect's body, it is easy to perceive 

 how fertilization may be effected in MonacTianthas viridis, as the 

 helmet or covering stands in the same position as in G, tridentatiim, 

 but if the pollen is deposited on the back of the insect it is necessary 

 that it should turn round while in the flower to bring the pollen in 

 contact with the stigmatic cavity of the plant, and this they often do 

 while visiting these flowers. This actually happens when the flower 

 is visited by a small golden-coloured bee, as is shown by a drawing of 

 Dr. Cruger in the Library of the Royal Botanic Gardens, which I 

 am able to confirm by actual observation. Darwin's trials, like all 

 his work, have been faithfully carried out, but they do not appear to 

 be conclusive, for it is seen that the pollen will not be ejected until 

 the separation layer of cells is mature, and that when this occurs 

 the liberation of the anther cap has the same eflPect as vibration pro- 

 duced by the touching of the antennae. In a flower of G. BungerotJiii 

 which was under observation, the pollen masses being liberated by 

 the removal of the anther cap, the caudicle, by its contraction, drew 

 them directly into the stigmatic cavity ; showing that under certain 

 circumstances self-fertilization would be effected. In another flower 

 of the same species, however, the pollinia were ejected by irritation of 

 the antennae. Darwin likens the position of the points of the antenn£e 

 to the position of the hands when in defence. Now in a drawing 

 made sixteen years ago, the position observed was as follows : — Look- 

 ing at the flower with point of column downwards — the right hand 

 horn or antenmij is always to be seen curved round the base of the 

 labellum at the same level as the attachment of the column, with the 

 apex pointing outwards. The left hand ''horn" grows straight to 

 the rear and curves upwards slightly towards the opening, and these 

 positions ai-e constant both in G. Banijerothii as well as in G. tridcn- 



