Chap. VI. ANGR^CTJM SESQUIPEDALE. 163 



What can be the use, it may be asked, of a nectary of 

 such disproportionate length ? We shall, I think, see 

 that the fertilisation of the plant depends on this 

 length, and on nectar being contained only within the 

 lower and attenuated extremity. It is, however, sur- 

 prising that any insect should be able to reach the 

 nectar. Our English sphinxes have proboscides as long 

 as their bodies ; but in Madagascar there must be 

 moths with proboscides capable of extension to a length 

 of between ten and eleven inches ! This belief of 

 mine has been ridiculed by some entomologists, but we 

 now know from Fritz Miiller * that there is a sphinx- 

 moth in South Brazil which has a proboscis of nearly 

 sufficient length, for when dried it was between ten 

 and eleven inches long. When not protruded it is 

 coiled up into a spiral of at least twenty windings. 



The rostellum is broad and foliaceous, and arches 

 rectangularly over the stigma and over the orifice of 

 the nectary : it is deeply notched by a cleft enlarged 

 or widened at the inner end. Hence the rostellum 

 nearly resembles that of Calanthe after the disc has 

 been removed (see fig. 26, C). The under surfaces of 

 both margins of the cleft, near their ends, are bordered 

 by narrow strips of viscid membrane, easily removed ; 

 so that there are two distinct viscid discs. A short 

 membranous pedicel is attached to the middle of the 

 upper surface of each disc ; and the pedicel carries a 

 pollen-mass at its other end. Beneath the rostellum 

 a narrow, ledge-like, adhesive stigma is seated. 



I could not for some time understand how the 

 pollinia of this Orchid were removed, or how the 

 stigma was fertilised. I passed bristles and needles 



■* See letter with a drawing by Hermaun Muller, ' Nature,' ISTS, 

 p. 223. 



M 2 



