Observations on Wood-Boring Insects, Their Parasites and Other Associated Insects

During the course of many years’ interest in the several groups of Parasitic Hymenoptera the writer has frequently been struck by the preponderance of primitive types which prey upon wood-boring insects. Not only this, but several of the most primitive families of phytophagous Hymenoptera develop mainly within the tissues of woody plants and an exceptionally large proportion of the leaf-feeding sawflies subsist upon the foliage of trees. These facts suggest that the early phylogenetic history of the Hymenoptera was in some way bound up in the deveopment of the woody flora and that this early assoc{ation has persisted to the present time without sufficient change to destroy the earmarks of past history in the modern hymenopterous fauna. The immediate occasion for the present discussion is a small, but quite varied collection of insects made during the past summer at my summer home in Petersham, Mass. Early in the season the attention of my wife was attracted by a considerable number of flying insects that had congregated upon the panes of a window in a room where the stove wood for the household is stored. This room contains an assortment of wood of various sizes and varieties, principally oak, chestnut, white pine, red maple and birch. The wood is cut in the nearby woodlot one year, allowed to season and then sawed, split and stored away the next year. Before storage, it has therefore an opportunity to be attacked by various wood boring insects and fungi together with the insects that are attracted to the latter. So many specimens appeared on the first day that collections were made daily upon the window from early July to late September and by the end of the season we had amassed a considerable collection. After sorting and identification, the fol-