“ A federal injunction to stay state criminal proceedings is an extraordinary remedy. Cf. Douglas v. City of Jeannette, 319 U.S. 157, 63 S.Ct. 877, 87 L.Ed. 1324; Ex parte Young, 209 U.S. 123, 28 S.Ct. 441, 52 L.Ed. 714. In addition to the considerations normally attending an application for such relief, a serious question of standing is presented on this motion, in that it appears that the movants themselves are not being prosecuted in the Mississippi courts. On the record before us the motion for a stay injunction pending appeal is denied. ”