Hello I watched this horror film ages ago it was about these bugs that killed people and wrote a message on a wall .think the lead character had a beard but could be wrong I know its not much to go on .any ideas please?

Bugs that could write and a lead character with a beard, and horror. Are you sure you don't mean a Monty Python movie ?

Tick

I remember that movie! They came up from deep earth, and could ignite fires with their legs, but, could withstand the flames. Can't remember the name, however, maybe this helps someone else!

Bug (1975)
An earthquake releases a strain of mutant cockroaches with the ability to start fires, which proceed to cause destructive chaos in a small town. The studies carried out by scientist James Parmiter, however, reveal worse consequences.