Wordnet 3.0
NOUN (1)
1. 
 tick lacking a dorsal shield and having mouth parts on the under side of the head; 
[syn: soft tick, argasid]
WordNet (r) 3.0 (2006):
argasid
    n 1: tick lacking a dorsal shield and having mouth parts on the
         under side of the head [syn: soft tick, argasid]