In 1945 injury to shoots of balsam fir, Abies balsamea (L.) Mill., by sawfly larvae was very common in York and Madawaska counties, New Brunswick. Since then, similar injury has been noticed throughout most of New Brunswick, eastern Nova Scotia, the upper peninsula of Michigan and northern Wisconsin.
New Brunswick specimens were identified by Dr. O. Peck of the Systematic Unit, Division of Entomology, as presumably Pleroneura borealis Felt, the specimens running to this species in Ross' Key (2); however, as stated by Ross (3), the recognition of species in the genus is not at present based upon fundamental characters. P. borealis was originally described in 1917 by Felt (1) from three specimens collected at Lake Clear, N.Y., in 1907. Except for the taxonomic revision by Ross (2), no other reference to this species was found in the literature.