Particularly since the concerns over Colony Collapse Disorder, newspapers and similar sources have repeatedly quoted a factoid about Einstein and bees. For instance, The Guardian had a classic exposition of the story recently in Last flight of the honeybee?: "According to Albert Einstein, our very existence is inextricably linked to bees - he is reputed to have said: 'If the bee disappears off the surface of the globe, then man would only have four years of life left'". This quote, with suitably qualified attribution, has been prominent in the publicity (as in the Guardian ad above) for the new book A World Without Bees by Alison Benjamin and Brian McCallum (Guardian Newspapers Ltd, ISBN 0852650922).
While loss of bees would almost certainly be disastrous, bibliographically at least the story appears bogus: there's no provable attribution to Einstein and, as Snopes.com says - Einstein on Bees - the story gained parlance in 1994 during a not entirely disinterested protest by the National Union of French Apiculture.
As to the comment about access to historical materials, I was interested to find a reference to this statement well predating 1994:
Professor Einstein, the learned scientist, once calculated that if all bees disappeared off the earth, four years later all humans would also have disappeared.
- The Irish Beekeeper, v.19-20, 1965-66, p74.
The source cited is Abeilles et Fleurs (i.e. Bees and Flowers), June 1965: which happens to be the house mag of the Union Nationale de l'Apiculture Française - same organisation which was propagating the story in 1994, and is still pushing it like mad. If the story originated in French, this might explain the difficulty Snopes.com mentions in antedating it.
Addendum. Techie aside: it does appear that the (alleged) Einstein statement is an exaggeration anyway. It had already crossed my mind that a number of important staple starchy crops are safe: potatoes, for instance, are propagated from sprouting tubers, and the cereal crops - which are all basically jumped-up grasses - are wind-pollinated. But I further had an interesting e-mail from Felix Grant who (as a 'roving scientist') has spoken to experts in the field of CCD. The general view was that loss of honeybees would be very nasty, but not a human extinction scenario. The status of bees as chief pollinators is largely an artificial one down to the human use of travelling monocultures of bees, which have an altered an ecology that bees originally shared with other pollinating species - moths, butterflies, hoverflies and other flies, beetles, etc. With loss of bees, with proper management these other pollinators would in time return to fill this niche.
Addendum 2: nice to see this making it to mainstream reportage: Einstein was wrong: Demise of bees won't bring humanity to its knees, Jenny Haworth, The Scotsman, 8th May 2009, which is citing Marcelo A. Aizen and Lawrence D. Harder. "The Global Stock of Domesticated Honey Bees Is Growing Slower Than Agricultural Demand for Pollination". Current Biology, 2009; DOI: 10.1016/j.cub.2009.03.071. The authors of this paper note that there appear to be political/economic factors, rather than biological ones, behind the growth in demand - only over the last 50 years - for pollination-dependent produce. More detail at ScienceDaily.
Addendum 3: I've since generalised the phenomenon, and postulate a term for false celebrity quotations: the Hillfinger.
Addendum 4: see That bee story (May 2010) again for an update; I've managed to track the roots of the story even further back, to a similarly fake attribution to Darwin.
Addendum 5: see 2012 update Einstein, Darwin and bee apocalypse.