Two species of fire-flies are abundant in western Massachusetts in the early summer and often their display of light presents a magnificent spectacle. Theses species are Photinus scintillans, Say, and Photuris Pennsylvanica, De Geer. Photinus scintillans becomes active very early in the evening, and long before twilight begins its orange-coloured light may be seen flashing among the shrubbery. It is only active during the twilight hour and some time before total darkness has set in its lights have disappeared.