The Collaborative International Dictionary of English v.0.48:

Gnatworm \Gnat"worm`\, n. (Zool.)
   The aquatic larva of a gnat; -- called also, colloquially,
   wiggler.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Wiggler \Wig"gler\, n. (Zool.)
   The young, either larva or pupa, of the mosquito; -- called
   also wiggletail.
   [1913 Webster]

WordNet (r) 3.0 (2006):

wiggler
    n 1: one who can't stay still (especially a child); "the toddler
         was a real wiggler on plane trips" [syn: wiggler,
         wriggler, squirmer]
    2: larva of a mosquito [syn: wiggler, wriggler]
    3: terrestrial worm that burrows into and helps aerate soil;
       often surfaces when the ground is cool or wet; used as bait
       by anglers [syn: earthworm, angleworm, fishworm,
       fishing worm, wiggler, nightwalker, nightcrawler,
       crawler, dew worm, red worm]