The Collaborative International Dictionary of English v.0.48:

Vellicate \Vel"li*cate\, v. i.
   To move spasmodically; to twitch; as, a nerve vellicates.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Vellicate \Vel"li*cate\, v. t. [imp. & p. p. Vellicated; p.
   pr. & vb. n. Vellicating.] [L. vellicatus, p. p. of
   vellicare to twitch, fr. vellere to pluck, pull.]
   To twitch; to cause to twitch convulsively.
   [1913 Webster]

         Convulsions, arising from something vellicating a nerve
         in its extremity, are not very dangerous. --Arbuthnot.
   [1913 Webster]

WordNet (r) 3.0 (2006):

vellicate
    v 1: touch (a body part) lightly so as to excite the surface
         nerves and cause uneasiness, laughter, or spasmodic
         movements [syn: tickle, titillate, vellicate]
    2: irritate as if by a nip, pinch, or tear; "smooth surfaces can
       vellicate the teeth"; "the pain is as if sharp points pinch
       your back" [syn: pinch, vellicate]