Wordnet 3.0
ADJECTIVE (2)
1. 
 immature of its kind; 
 especially being or characteristic of immature insects in the newly hatched wormlike feeding stage; 
- Example: "larval societies"- Example: "larval crayfishes"- Example: "the larval stage"2. 
 relating to or typical of a larva; 
- Example: "the larval eye"
The Collaborative International Dictionary of English v.0.48:
larval \lar"val\ (l[aum]r"val), a. [L. larvalis ghostly. See
   Larva.] (Zool.)
   Of or pertaining to a larva.
   [1913 Webster]
WordNet (r) 3.0 (2006):
larval
    adj 1: immature of its kind; especially being or characteristic
           of immature insects in the newly hatched wormlike feeding
           stage; "larval societies"; "larval crayfishes"; "the
           larval stage"
    2: relating to or typical of a larva; "the larval eye"