% Comment in the lines from \documentclass to \begin{document}
% and from \write18 to \end{document}
% to use the standalone package for testing the Feynman graphs
% You should also change the fmffile name to ep_cc-mp
% \documentclass{standalone}

% \usepackage{feynmp}
% \DeclareGraphicsRule{*}{mps}{*}{}

% \unitlength=1mm
% \begin{document}
\begin{fmffile}{feynexa}
\begin{fmfchar*}(40,25)
  \fmfleft{em,ep}
  \fmf{fermion}{em,Zee,ep}
  \fmf{photon,label=$Z$}{Zee,Zff}
  \fmf{fermion}{fb,Zff,f}
  \fmfright{fb,f}
  \fmfdot{Zee,Zff}
\end{fmfchar*}
\end{fmffile}
% Include this command for Metapost
% \write18{mpost feynexa-mp}
% \end{document}
