270 SECRETION OF NECTAR. Chap. IX 



IS covered with longitudinal, fimbriated ridges. In 

 several species of Ophrys, there are two small shining 

 protuberances, at the base of the labellum, beneath the 

 two discs. Innumerable other cases could be added of 

 the presence of singular and diversified excrescen'ces 

 on the labellum ; and Lindley remarks that their use 

 is quite unknown. 



From the position, relatively to the viscid discs, 

 which these excrescences occupy, and from the absence 

 of any free nectar, it formerly seemed to me highly 

 probable that they aftbrded food and thus attracted 

 either Hymenoptera or flower-feeding Coleoptera. 

 There is no more inherent improbability in a flower 

 being habitually fertilised by an insect coming to 

 feed on the labellum, than in seeds being habitually 

 disseminated by birds attracted by the sweet pulp in 

 which they are embedded. But I am bound to state 

 that Dr. Percy, who had the thick and furrowed 

 labellum of a Warrea analysed for me by fermentation 

 •over mercury, found that it gave no evidence of con- 

 taining more saccharine matter than the other petals. 

 On the other hand, the thick labellum of Catasetum 

 and the bases of the upper petals of Mormodes ignea, 

 have a slightly sweet, rather pleasant, and nutritious 

 taste. Nevertheless, it was a bold speculation that 

 insects were attracted to the flowers of various Orchids 

 in order to gnaw the excrescences or other parts of 

 their labella; and few things have given me more 

 satisfaction than the full confirmation of this view by 

 Dr. Criiger, who* has repeatedly witnessed in the West 

 Indies humble-bees of the genus Euglossa gnawing 

 the labellum of Catasetum, Coryanthes, Gongora, and 

 Stanhopea. Fritz Miiller also has often found, in 



• Journ. Linn. Soc. Bot.' 186J, vol. viii. p. 129. 



