The Collaborative International Dictionary of English v.0.48:

Sylphid \Sylph"id\, n. [F. sylphide, fem. See Sylph.]
   A little sylph; a young or diminutive sylph. "The place of
   the sylphid queen." --J. R. Drake.
   [1913 Webster]

         Ye sylphs and sylphids, to your chief give ear,
         Fays, fairies, genii, elves, and demons, hear. --Pope.
   [1913 Webster]