The third-stage larva (L3) develops in the feces or on the soil after the first-stage larva (L1) hatches from the egg. The larva is rather nondescript but this photo shows that it is sheathed, i.e. it has retained the cuticle of the previous stage after its last molt.Many nematodes do this because the old cuticle provides a barrier that helps them resist desiccation. The old cuticle is visible as a "halo" around the larva.