CflAP. V. CATTLETA. 145 



tubular, and its lower part is produced into a nectary, 

 which penetrates the ovarium. 



Now for the action of these parts. If any body of 

 size proportional to that of the tubular flower be 

 forced into it — a dead humble-bee acts very well — the 

 tongue-shaped rostellum is depressed, and the object 

 often gets slightly smeared with viscid matter ; but 

 in withdrawing it, the rostellum is upturned, and a 

 surprising quantity of viscid matter is forced over the 

 edges and sides, and at the same time into the lip of 

 the anther, which is also slightly raised by the up- 

 turning of the rostellum. Thus the protruding tips 

 of the caudicles are instantly glued to the retreating 

 object, and the poUinia are withdrawn. This hardly 

 ever failed to occur in my repeated trials. A living 

 bee or other large insect alighting on the fringed 

 edge of the labellum, and scrambling into the flower, 

 would depress the labellum and would- be less likely 

 to disturb the rostellum, until it had sucked the 

 nectar and began to retreat. When a dead bee, with 

 the four waxy balls of pollen dangling by their 

 caudicles from its back, is forced into another flower, 

 some or all of them are caught with certainty by the 

 broad, shallow, and highly viscid stigmatic surface, 

 which likewise tears off the grains of pollen from the 

 threads of the caudicles. 



That living humble-bees can thus remove the 

 poUinia is certain. Sir W. C. Trevelyan sent to Mr. 

 Smith of the British Museum a Bonibus hortorum, 

 which was forwarded to me — caught in his hothouse, 

 where a Cattleya was in flower — with its whole back, 

 between the wings, smeared with dried viscid matter, 

 and with the four pollinia attached to it by their 

 caudicles, ready to be caught by the stigma of any 

 other flower if the bee had entered one. 



