Measurement of Semileptonic Decays of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>D</mml:mi></mml:math>Mesons to Electrons at the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>ψ</mml:mi><mml:mn/><mml:mo>(</mml:mo><mml:mn>3772</mml:mn><mml:mo>)</mml:mo><mml:mn/></mml:math>

We have observed anomalous electron production in multiprong events produced by ${e}^{+}{e}^{\ensuremath{-}}$ annihilation at the $\ensuremath{\psi}(3772)$. For electron momenta greater than 300 MeV/c we measure an anomalous electron production cross section of 1.1 \ifmmode\pm\else\textpm\fi{} 0.3 nb. The measured spectrum is consistent with that expected for semileptonic $D$ decay. With reasonable assumptions we find the branching ratio for $D$ decay to an electron plus additional particles, averaged over the neutral and charged $D$, to be (7.2\ifmmode\pm\else\textpm\fi{}2.8)%.