Shore fly maggot, Ephydridae (Iowa). I found this almost-microscopic larva swimming near the surface of an algae-covered pond. The breathing tubes on the posterior end (called spiracles) function like tiny snorkels, allowing the larvae to breathe underwater.
Colorado Potato Beetle larva, Leptinotarsa decemlineata, from Roseville, Minnesota.
Common sawfly larva (Tenthredinidae: Eriocampa sp.) from Roseville, Minnesota.
