Black-hole dyons need not explode

During the final stage of black-hole evaporation particles of all kinds will be emitted, including exotic states not normally seen in the laboratory. Among them could be magnetic monopoles. This process is discussed. It is found that the presence of electric charge on the hole reduces the emission compared with that from a neutral hole. An interesting consequence of this is that a primordial black hole possessing both electric and magnetic charge (a black-hole dyon) need not explode but may end its life as an extreme Reissner-Nordstr\"om black hole, with finite mass and zero temperature. The application of these results to other gauge theories is briefly discussed. An appendix treats the Dirac equation in curved space using Geroch, Held, and Penrose and spin-weighted spherical-harmonic techniques.