This insect was first noticed during the summer of 1939 in a young red pine plantation in the vicinity of Berthierville, Que. A large number of mature larvae were collected at the end of the same season and placed on the foliage of small red pine trees enclosed in wire cages in the field. The larvae soon left the trees to enter the soil for overwintering. The following spring, numerous adults emerged in the cages, and in order to obtain an identification, several specimens were sent to Dr. O. Peck, Entomology Division, Ottawa, who considered that this was apparently a new species of the genus Cephalcia. Later, many specimens were sent to Dr. W. W. Middlekauff, of the University of California, who described the species under the name C. marginata (1953).