There seems to be some disagreement among entomologists (and etymologists) about whether bees actually have knees. Some insist that knees have to have kneecaps (which bees don’t have) while others are content to regard any mid leg joint as a knee. Either way the middle section of this common carder bee’s leg is fine and hairy.
I can’t make sense of this white tailed bumblebee’s legs, let alone his or her knees. The front pair of legs seem to be wrapped round the insect’s neck, not so surprising when you learn that the front legs have notches specially adapted for cleaning the bee’s antennae.
A long-tongued garden bumblebee; a different shape of leg and very furry thighs.
Used as an expression of excellence or self satisfaction ‘the bee’s knees’ suggests that there might also be something special about the real knees of the bee. A contributor to discussion of the subject on the Naked Scientist podcast of the University of Cambridge (no less) suggested that the hairy ‘baskets’ used to collect pollen behind the back leg knees of a bee could make the bee’s knees look like ‘something very big and spectacular’.
The Guardian Notes and Queries addressed the question under the heading of Semantic Enigmas, eliciting contributions about the be-all and end-all’s, abbreviated to Bs and Es, and the suggestion that ‘bee’s knees’ is somehow a corruption of the word business. BBC Science Focus has the most straightforward explanation of them all: knees rhymes with bees…..