ME. R, TRIMEN ON THE STRTJCTUHE OF BONATEA SPECIOSA. 159 



disks to some portion of the underside of the head or prohoscis 

 seems inevitable. It is right to mention that I found no nectar 

 in either of the three nectaries that I opened ; but it is possible 

 that this was owing to cultivation in a greenhouse. 



But supposing, on the other hand, that the^nectary is well- 

 filled with nectar, it would seem just possible, from the polliuia- 

 disks being so far in front and the rostellum-helmet so widely 

 open above, that a moth or fly with a long and flexible proboscis 

 might obtain nectar without removing either poUinium. Few 

 persons, indeed, who have watched the impetuous eagerness with 

 which SpMngidce and the larger Noctum rifle the honey of flowers, 

 would consider it likely that the rapidly probing proboscis could 

 avoid both disks 



Noctua 



) 



landing-place afforded by the many cohering organs, and have to 



arms 



the rostellum. Yet such a chance does exist, and nature has 

 provided against it. Immediately in front of the orifice of the 

 nectary, back in the throat of the helmet, a stout, erect, white 

 process or peg, rather more than a line in length and very slightly 

 curved forwards at its apex, springs from the central portion of 

 the labellum, and eflfectually bars any direct access to the nectary, 

 only leaving a very small space on either side of it, through which 

 the proboscis can be inserted (see fig. E). An insect is therefore 

 compelled to make its approach to the nectary a little to one side 

 or the other, and thus the attachment of one of the backward and 

 laterally facing disks is absolutely ensured. 



withdraw 



natural 



great 



very long caudicle is not thus overcome to any 



downward perpendicular 



the disk (see fig. F). The position thus naturally assumed is ad- 



grams 



the viscid surface of the strangely produced and slightly depen- 

 dent stigmas, which no pollinium with a shorter caudicle would 



than 



be likely to reach. 



certainty with which the pollen-masses, when attached to a slender 



pin which had 



nectarial 



stigm 



The 



atory 



