flying stag = French cerf-volant, a stag-beetle.extracted from flyingadj.
flying stag
†f.transferred. flying stag, the stag-beetlen.Obsolete.
ΚΠ
1658 J. Rowland tr. T. Moffett Theater of Insects in Topsell's Hist. Four-footed Beasts (rev. ed.) 1005 The πλατύκερως, or Harts horn Beetle... Some call it the Bull, others the flying Stag... The French, Cerf volant; the English, Stag-fly, or Flying-fly.