Ancillary services are those functions performed by electrical generating, transmission, system-control, and distribution-system equipment and people to support the basic services of generating capacity, energy supply, and power delivery. The Federal Energy Regulatory Commission defined ancillary services as ``those services necessary to support the transmission of electric power from seller to purchaser given the obligations of control areas and transmitting utilities within those control areas to maintain reliable operations of the interconnected transmission system.`` FERC identified six ancillary services reactive power and voltage control, loss compensation, scheduling and dispatch, load following, system protection, and energy imbalance. Our earlier work identified 19 ancillary services Here we offer a revised set of seven ancillary services and mention several other services that merit consideration. In preparing its final rule on open-access transmission service, we suggest that FERC consider splitting its system-protection service into its two primary pieces, reliability reserve and supplemental-operating reserve. We also suggest that FERC define more sharply all of the ancillary services. especially load-following reserve and energy imbalance. Finally, we suggest that FERC consider other services and their provision in a restructured electricity industry; these services include black-start capability, time correction, standby service. planning reserve, redispatch. transmission services, power quality, and planning and engineering services.