Life histories of Conophthorus beetles attacking the shoot tips of jack, red, Scotch, and ponderosa pines were studied and compared with the life history of the red pine cone beetle, Conophthorus resinosae Hopkins. The tip-infesting beetles have not been morphologically separated from C. resinosae. The beetles attacking the shoots of jack, red, Scotch, and ponderosa pines have similar life histories which differ from that of C. resinosae. The latter is distinctly univoltine, while the tip-infesting beetles appear to be bivoltine. Also, dates of appearance and seasonal development differ.