Observations of Jupiter's auroral H2 emissions with the IUE spacecraft, from 1978 through 1990, show that aurorae at the two poles are similar in several respects: (a) emission intensity is modulated with magnetic longitude, north peak emission at &lgr;III (1965) ~200¿, south peak at &lgr;III(1965)~20¿; (b) emission intensity and degree of modulation are comparable for both poles; (c) attenuation by hydrocarbons varies in phase with the intensity, peak attenuation coinciding approximately with peak emission. Increases in the hydrocarbon column are an indicator of either enhanced penetration depth and thus energy of the auroral primaries, or of increases in the high-altitude hydrocarbon content caused by modification of the local atmosphere. ¿American Geophysical Union 1990