Click beetle  (Lacon quercus)

Elytra: in beetles and earwigs, the hard fore wings. They are held aloft when the insect flies, and are often coloured or patterned.
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.
Pupate: the process of forming a pupa, the stage in 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.

1. National Biodiversity Network Species Dictionary (September 2002)
   http://www.nhm.ac.uk/nbn
   
2. Key, R. (January, 2004) Pers. comm
   
3. Shirt, D. B. (1987) British Red Data Books: 2 Insects. Nature Conservancy Council, Peterborough.
   
4. Personal observation from images.
   
5. Harde, K. W. (2000) A field guide in colour to beetles. Silverdale Books, Leicester.
   
6. UK BAP (September 2002)
   http://www.ukbap.org.uk
   
7. Cheesman, O.D (2003) (unpublished). Research on saproxylic invertebrates and their conservation in the UK (contract FST 20-37-02) Final report. CABI report xB1992. CABI Bioscience. Egham Surrey.