The Collaborative International Dictionary of English v.0.48:

Wichitas \Wich"i*tas\ (w[i^]ch"[i^]*t[add]z), prop. n. pl.;
   sing. Wichita (w[i^]ch"[i^]*t[add]). (Ethnol.)
   A tribe of Indians native of the region between the Arkansas
   and Red rivers. They are related to the Pawnees. See
   Pawnees.
   [1913 Webster] wick