Lulworth skipper  (Thymelicus acteon)

Calcareous: Containing free calcium carbonate, chalky.
Hibernate: A winter survival strategy characteristic of some mammals in which an animal's metabolic rate slows down and a state of deep sleep is attained. Whilst hibernating, animals survive on stored reserves of fat that they have accumulated in summer. In insects, the correct term for hibernation is 'diapause', a temporary pause in development and growth. Any stage of the lifecycle (eggs, larvae, pupae or adults) may enter diapause, which is typically associated with winter.
Larvae: Stage in an animal's lifecycle after it hatches from the egg. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.
Pupation: The process of becoming a pupa, the stage of an insect's development, when huge changes occur that reorganise the larval form into the adult form. In butterflies the pupa is also called a chrysalis.
Single-brooded: Also known as ‘univoltine'. Referring to an organism which has just one brood each year.

1. Still, J. (1996) Collins Wild Guide: Butterflies and moths of Britain and Europe. HarperCollins Publishers, London.
   
2. Carter, D.J. and Hargreaves, B. (1986) A Field Guide to Caterpillars of Butterflies and Moths in Britain and Europe. Collins, London.
   
3. Asher, J., Warren, M., Fox, R., Harding, P., Jeffcoate, G. and and Jeffcoate, S. (2001) The Millennium Atlas of Butterflies in Britain and Ireland. Oxford University Press, Oxford.
   
4. Bourn, N.A.D. and Warren, M.S. (1997) Species Action Plan: Lulworth Skipper, Thymelicus Action. Butterfly Conservation, Wareham. Available at:
   http://www.butterfly-conservation.org/downloads.asp?PageId=73