Caliroa
Caliroa is a genus of sawflies in the family Tenthredinidae. The larvae are slimy in appearance, and are sometimes referred to as "slugs" although they are insects rather than gastropods.
The larvae of some species in this genus are important pests which can do significant damage to the leaves of trees such as oaks, poplars, and cherry and pear trees. The larvae are covered in slime, making them unpalatable to predators; when fully grown, they drop off the tree and pupate underground.