(Sawfly, shaking her wings to dry them out)
The larvae of sawflies look very much like caterpillars, in fact I have often mistaken them for caterpillars, only to learn via bugguide.net or other resource that I was wrong. The following are some examples of sawfly larvae. Each species of sawfly is usually host specific and will be found on its own particular food choice.
(Found on Elderberry Bush)
(Found on Poison Ivy)
(Found on grasses)
(Found on Elm Tree)
As you can see the diversity of these larva is incredible, and I just love finding them and photographing them. You can also see how very much they look like caterpillars. One key difference Caterpillars can have up to five pairs of abdominal prolegs, but never have more than five pairs. Sawfly larvae always have six or more pairs of abdominal prolegs.
Here is a couple of diagrams to help you ID your caterpillar or sawfly larvae.
I can hardly wait until the weather finally warms up and stays warm so I can get outside and look for these wonderfully unique insects.