We performed a photoemission investigation of the electronic structure of PrNiO3 and NdNiO3 through the first order (paramagnetic) metal to (antiferromagnetic) insulator transition. Surprisingly, the data reveal a temperature-dependent loss of spectral weight near the chemical potential, which extends well below the coincident metal-insulator (T-MI) and magnetic (T-Neel) transition temperatures. This is in contrast with the behavior in SmNiO3 and EuNiO3, where the two transitions are separate. The spectral properties clearly indicate two distinct regimes for RNiO3 with T-MI = T-Neel and T-MI > T-Neel.