On two occasions adult males of Stratiomys badius Walker gave my thumb a painful prick with their sharp scutellar spines. In both instances I had grasped the fly with my thumb and index finger through the mesh of an aerial net, and I could feel it squirm slightly in my grasp as it drove the scutellar spine (s?) into the ball of my thumb. There was enough pain to make me withdraw my hand involuntarily–about equivalent to the prick of a fine insect pin. The spines might well have had a similar effect if the fly had been held in the bill of a bird or in the jaws of some other vertebrate.