Diprionidae

The Diprionidae are a small family of conifer-feeding sawflies (thus the common name conifer sawflies, though other Symphyta feed on conifers) restricted to the Northern Hemisphere, with some 140 species in 13 genera worldwide. Larvae are often gregarious, and sometimes there can be major outbreaks, thus these sawflies can be major forest pests at times. The family is distinctive in having antennae with about 20 flagellomeres, and serrate or pectinate.