Females have a saw-like ovipositor at the tip of the abdomen and are larger than males.

[2] N. pinetum is native to North America, its range extending through the eastern United States to southeastern Canada.

The female uses its ovipositor to cut a slit along the edge of a pine needle and lays several eggs in this.

[5] When the larvae are fully developed, they descend to the ground where they make cocoons among the leaf litter; in these they overwinter as non-feeding prepupae, pupating in the spring and emerging as adults a few weeks later.

[2] Several parasitic wasps attack the larvae of this sawfly, and the egg parasitoid Closterocerus cinctipennis was found to be 90% effective in controlling an outbreak of the pest in Crawford County, Wisconsin.