This paper has been extracted mainly from the manuscript of a revision of the tortricid subfamily Archipinae, to make available a scientific name for an injurious, undescribed Choristoneura species that feeds in the larval stage upon pines, particularly jack pine, Pinkus banksiana Lamb., and red pine, P. resinosa Ait. This insect and the closely allied Choristorneura fumiferana Clem. are compared under the following topics: taxonomic history, maculation, morphology, and distribution. References are cited only if they contain information of taxonomic significance; the vast amount of economic literature dealing with these species has been omitted. This paper is followed by a comparative study of the larvae of the two species by Miss M. MacKay, by one by Miss C. E. Cox on the mathematical significance of the anatomical differences in the larvae and adults of both species, by a discussion of some of the parasites of the pine species by G. S. Walley, and by a discussion by S. G. Smith of the isolating mechanisms aperating between the two species.