[tangoblue (OP)]

does anyone know what the hard shell that opens on a beetle is called.

[Bored chemist]

Carapace?

[LeeE]

Carapace was the first thing that sprung to my mind too, but carapaces don't open.  I believe that what tangoblue is thinking of are called the Wing Covers.

[RD]

elytron, elytrum  n. (pl. -ra) insect's hardened forewing, forming case for hind wing.

http://www.talktalk.co.uk/reference/dictionaries/difficultwords/data/d0005034.html

http://en.wikipedia.org/wiki/Elytron

[LeeE]

elytron, elytrum  n. (pl. -ra) insect's hardened forewing, forming case for hind wing.

http://www.talktalk.co.uk/reference/dictionaries/difficultwords/data/d0005034.html

http://en.wikipedia.org/wiki/Elytron

Yup, that's the fella.  I think I've also heard them called Wing Cases too.

[tangoblue (OP)]

The carapace rings a bell, i thaught that there was only one outside 'hard shell'.