78 OPURE^. Chap. II. 



nectar anc ''.hat the flowers are very conspienous, it 

 is remarkable that they are rarely visited by insects. 

 Mi: 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 lias more than once seen a large fly, 

 allied to Bombylius, with the pollinia oiDisa pohjgnoides 

 attached to the base of its proboscis. IMr. AA'eale states* 

 that D. macrantlia differs from D. grandijiora 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 brino- them into contact with the stifi-ma. 

 This in nature is not unseldoni 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. grandijiora in being so seldom fertilised by insects 

 offers a case like that of Ophrys mnscifera ; whilst 

 D. macrantlia in being often self-fertilised closely cor- 

 responds with Ophr7js apifera ; but this latter species 

 seems to be invariably self-fertilised. 



Lastly, Mr. Weale has described,! 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 hav3 now^ finished with the Ophrea? ; but before 

 passing on to the following tribes, I will recapitulate 



* '.Joiirn. I.iiTi. Soc. Bot.* vol. t ' Journ. Linn. Soc. Bot.' vol 



xiii. 1S71, p. 4.1 xiii. 1S71, p. 42. 



