Sentence:  Now that was in summer, the time of fleas and <WSD>glegs</WSD> and golochs in the fields, when stirks would start up from a drowsy cud-chewing to a wild a feckless racing, the <WSD>glegs</WSD> biting through hair and hide to the skin below the tail-rump. 
Meaning of the word marked with <WSD> tags:  A blood-sucking fly of the family (Tabanidae); a gadfly, a horsefly.