How do bucket orchids attach pollinia to a bee's body?

Bucket orchids (Coryanthes) utilize a specialized, coevolutionary mechanism to attach pollinia to male euglossine bees.12

The process functions as follows:

• Attraction and Entrapment: Male euglossine bees are drawn to the strong odor produced by the orchid's hypochile. While attempting to collect this scent, the bees often lose their footing and fall into the water-filled, waxy-sided "bucket" (epichile) of the flower.12
• Forced Exit: Because the bucket's sides are too slippery to climb, the bee is forced to crawl through a narrow tunnel formed by the apex of the column and the epichile.12
• Attachment: As the bee squeezes through this restricted exit, the orchid deposits the pollinarium—a structure containing the pollinia—onto the bee's thorax.12

Once the bee escapes, it carries the pollinia to the next flower it visits, where the pollen may be deposited onto the stigma, completing the pollination process.12