How do you find the following joke funny?

Not really, termites don't eat alone. You can end the joke with:

So the barman throws the termite out: 'No druggies allowed!"

The termite says 'What? I'm no druggie!'

. . . the barman replies 'What about the bar-bit-u-ate?'

You assume that the bar is made out of old fashioned wood.

Naturally the termite would like to eat tender wood instead of hard wood.

Just termite asking for bartender is fanny, but not that much.

30 years ago when I first heard it it was funny, but it's a little dated now

Because your making temite + bartender sound alike

he should be looking for the bar for that is what he will eat

I don't find this one funny at all! Where is the punchline?

I don't find it funny.

i dont

you don't. its not.