The hemlock borer (Melanophila fulvoguttata Harr.) belongs to a buprestid genus, the larvae of which bore in the bark and cambial area of the stems of conifers. They generally breed in trees which have been weakened. injured, or recently felled. Several species, however, including fulvoguttata, are reported to be capable of attacking and killing healthy trees and doing a large amount of damage. In other words, they belong to that class of cambial feeders which normally finds conditions most favorable when the host is about to die, but occasionally appears to be capable, when numerous, of breeding in healthy trees which would otherwise live. They are faculative tree killers.