In collecting sawfly eggs, larvae, and cocoons for propagating beneficial insects at the Belleville laboratory, a heavy infestation of a pine sawfly, Neodiprion nanulus Schedl, was discovered in 1942 nine miles north of Belleville, on a 25-year-old plantation of red pine, Pinus resinosa Ait.; Scots pine, Pinus sylvestris L.; and jack pine, Pinus banksiana Lamb.

From samples of the eggs collected in the spring of 1943, no parasites emerged.