Roseslugs are caterpillar-like insects that are actually the larval form of stingless wasps called sawflies. When trying to differentiate between caterpillars and sawfly larvae, count the number of “pro-legs” on the back of the insect. There will be six true legs on the thorax and then there will be six or more prolegs on sawfly larvae versus five or fewer prolegs on caterpillars. Roseslug larvae are lime green, with an orange-red head capsule and they can be up to a half inch long. When they are small, they create windowpane damage on leaves but as they grow they can chew all the way though a leaf leading to holes/skeletonization. Most of the damage will occur between May and June.