Cleg

Sir Christopher Pack did cleave like a clegg, and was very angry he could not be heard ad infinitum.

Source: wiktionary

Now that was in summer, the time of fleas and glegs and golochs in the fields, when stirks would start up from a drowsy cud-chewing to a wild a feckless racing, the glegs biting through hair and hide to the skin below the tail-rump.

Source: wiktionary

The clegs continue to swarm all around. I wonder how many there are.[…]Remaining seated on the block, I seize clegs out of the surrounding air at random, and with scissors cut out a tiny triangle from the rear edge of each one's right wing before releasing it.

Source: wiktionary

Cattle were grazing languidly on the lush grass and flicking their tails to keep away the clegs that constantly plagued them and, having recently suffered a nasty bite from one, I was wary of them myself.

Source: wiktionary