  The in-plane optical conductivity of UPd_2Al_3 was measured at temperatures
$2 {\rm K}<T<300$ K in the spectral range from 1 cm^{-1} to 40 cm^{-1} (0.14
meV to 5 meV). As the temperature decreases below 25 K a well pronounced
pseudogap of 0.2 meV develops in the optical response. In addition we observe a
narrow conductivity peak at zero frequency which at 2 K is less than 1 cm^{-1}
wide but which contains only a fraction of the delocalized carriers. The gap in
the electronic excitations might be an inherent feature of the heavy fermioin
ground state.
