A preliminary kinetic analysis is presented of the effects of variation along the magnetic field lines on Kelvin Helmholtz instabilities driven by transverse velocity shear. These develop provided the parallel variation is much less than the transverse, k∥ls <(m/M)1/2k⊥rL, where rL is the ion gyroradius and ls the shear length. They produce small parallel electric fields, but substantial potential drops along field lines.