A butterfly found perfectly preserved inside a Cambridge University library book may have been there for almost 400 years.
Head of Library Services at Trinity College Jenni Lecky-Thompson was shocked after discovering the insect in a specialist book from 1634.
College officials have said there is a possibility the original owner could have placed it in Theatre of Insects, which is the earliest insect book published in England.
They added the butterfly was “as colourful as the day it was pressed between the book’s pages”.
Watch: Rare preserved butterfly found in a copy of insect book
Lecky-Thompson said: “I was looking at some of the fantastic animal books we have and I was going through the pages of the wonderful Theatre of Insects, or Insectorum sive Minimorum Animalium Theatrum to give it its true title.
“While looking through our copy I chanced upon a butterfly (a small tortoiseshell I think) next to its accompanying image.
“There is a striking similarity between the woodcut and butterfly, which of course was the intention so that the various species could be identified by the amateur insect enthusiast.
“It is relatively common to find botanical specimens inside old books, but unusual to find an insect specimen.
“This one could have been put there by the first owner back in the 17th century, and if so it is amazing that is has survived there for so long.”
Former Trinity Hall undergraduate Lawrence Strangman's niece Geraldine Essayan donated the book to Trinity Collge in his memory in 1996.
The college said ‘he was a passionate book collector whose antiquarian books included early books on natural history.’
Trinity Hall added that even if the insect was put there more recently, it would have been there before the book arrived at the library in the 1990s.
Librarian Lecky-Thompson also found 17th-century advice from apothecary James Petiver which detailed how insects should be preserved.
It said: “Butterflies must be put into your Pocket-Book or any other small printed book as soon as caught after the same manner as you dry plants.”