larval stage nymph ammocoete trochophore stage leptocephalus wriggler A distinct juvenile stage many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. metacestode veliger nauplius stage grub maggot stage glochidium maggot naiad, nymph bipinnaria leptocephalus stage larva nymph stage caterpillar stage ammocoete stage zoea stage caterpillar larva stage glochidium stage trochophore planula nauplius wriggler stage zoea bipinnaria stage veliger stage naiad, nymph stage planula stage tornaria grub stage life cycle stage