During the month of May, 1896, while making field observations in Malden and Medford, Mass., upon the insects known to attack the gypsy moth (Porthetria dispar), I found that many of the common predaceous bugs upon emerging from hibernation greedily availed themselves of the food supply offered by the tent caterpillar and destroyed large numbers of this insect. Podisus placidus, P. serieventris, P. modestus, Dendrocoris humeralis, Euschistus fissilis, E. tristigmus, E. ictericus, E. politus n. sp., Menecles insertus and Diplodus lividus were often found feeding upon partially grown tent caterpillars. Podisus placidus and P. serieventris enter the tents and prey upon the inmates, but the other species generally attacked the larvæ while they were feeding. The species of Euschistus are the least predaceous and it is probable that they naturally feed more upon plants than upon insects.