Dragonfly

"They are often associated with snakes, as in the Welsh name gwas-y-neidr, "adder's servant".  The Southern United States term "snake doctor" refers to a folk belief that dragonflies follow snakes around and stitch them back together if they are injured."

http://en.wikipedia.org/wiki/Dragonfly

http://cy.wikipedia.org/wiki/Gwas_y_neidr