Do you know what kind of caterpillar this is? They were on our blueberry bush!
These are caterpillars in the genus Datana. Datana major, the Azalea Caterpillar is most likely and they appear to be early instars that will get more colorful as they grow and molt. You can read more about this species on BugGuide, where it is reported that they are sometimes found on blueberry leaves. The posture and group grazing of this genus are quite unique.