Larva ID Tips: Beetles
Caution: There is a lot of variety in larval forms, and they are difficult to identify. Here are a few tips.
Larvae have a well-developed head with chewing mouthparts. The abdomen does not have prolegs, but may have gills.

Figure 8.I: Peltodytes larva and adult (Haliplidae).
Image from URL: http://watermonitoring.uwex.edu/