Abstract: Lamp having an elongated lighting assembly and a guard assembly therefor. The lighting assembly includes an elongated fluorescent bulb characterized by hot regions at the end portions of its luminous envelope. The guard assembly includes: a tubular light-transmitting housing of polycarbonate or glass; metal end housings; and closure members closing the open outer ends of the end housings. Heat conductive metal bushings are cemented to the end portions of the light-transmitting housing. These have cylindrical bearing surfaces telescopically assembled in contiguous, lapping, heat-conductive relationship with corresponding bearing surfaces on the end housings. The metal bushings function as heat sinks and heat conductors, cooling the portions of the light-transmitting housing which are subject to radiation from the hot regions of the bulb by conducting heat through the bushings into the metal end housings which dissipate it to the surroundings.