[1][2] It is native to western North America, and it is being studied as a biological control agent for the hemlock woolly adelgid.

[7] The predatory life history of Laricobius is unique among the family as most derodontids are fungal feeders.

It can be found throughout the western U.S. and Canada, and specimens in the U.S. Museum of Natural History have been collected as far north as the southeastern Yukon.

[9] L. nigrinus goes through four larval instars, and the larvae use secretions to glue debris and adelgid wool to themselves as camouflage.

[7] Fourth instar larvae drop to the ground as prepupae and complete their development in the soil before emerging as adults in the fall.

Due to its narrow prey specificity and geographic range, L. nigrinus was approved by USDA-APHIS for release as a biological control agent in 2000.

[8] Field releases began in 2003, and populations have expanded to cover a wide range of A. tsugae infestation.

[15] Studies are ongoing to determine the rate of hybridization between L. nigrinus and its native congener, Laricobius rubidus which feeds on pine bark adelgid.