nectar and that the flowers are very conspicuous, it is remarkable that they are rarely visited by insects. Mr. Trimen wrote to me in 1864 that he had lately examined seventy-eight flowers, and only twelve of these had one or both pollinia removed by insects, and only five had pollen on their stigmas. He does not know what insects occasionally fertilise the flowers; but Mrs. Barber has more than once seen a large fly, allied to Bombylius, with the pollinia of Disa polynoides attached to the base of its proboscis. Mr. Weale states[1] that D. macrantha differs from D. grandiflora and cornuta in producing plenty of seed, and is remarkable from often fertilising itself. This follows from "a very slight jerk, when the flower is fully expanded, sufficing to eject the pollinia from their widely open anther-cases, and to bring them into contact with the stigma. This in nature is not unseldom the case, as I have repeatedly found many flowers thus fertilised." He has, however, no doubt that the flowers are likewise cross-fertilised by nocturnal insects. He adds that D. grandiflora in being so seldom fertilised by insects offers a case like that of Ophrys muscifera; whilst D. macrantha in being often self-fertilised closely corresponds with Ophrys apifera; but this latter species seems to be invariably self-fertilised.
Lastly, Mr. Weale has described,[2] as far as he could make out, the manner in which a species of Disperis is fertilised by the aid of insects. It deserves notice that the labellum and two lateral sepals of this plant secrete nectar.
We have now finished with the Ophreæ; but before passing on to the following tribes, I will recapitulate
