# Missing labels with feynmf/feynmp?

I am using feynmp to generate Feynman diagrams with pdflatex. Everything seems to be working but my labels are not showing up.

What is wrong?

\documentclass{minimal}
\usepackage{feynmp}

% Needed to interpret generated *.1, *.2 etc. as ps files.
\DeclareGraphicsRule{*}{mps}{*}{}

\begin{document}
Here is a vertex for a local potential in momentum space:
\begin{fmffile}{fgraphs}
\begin{fmfgraph}(40,30)
% Note that the size is given in normal parentheses instead of curly
% brackets in units of \unitlength (default 1pt).
\fmfleft{i1,i2} % Define external vertices from bottom to top
\fmfright{o1,o2}
\fmf{fermion}{i1,v1,o1}
\fmf{fermion}{i2,v2,o2}
\fmf{photon,tension=0.3}{v1,v2}

% These labels are missing!
\fmflabel{$\vec{p}$}{i1}
\fmflabel{$\vec{q}$}{i2}
\fmflabel{$\vec{p}+\vec{k}$}{o1}
\fmflabel{$\vec{p}-\vec{k}$}{o2}
\end{fmfgraph}
\end{fmffile}
\end{document}


Save this to tst.tex and compile with:

pdflatex tst
mpost fgraphs
pdflatex tst
pdflatex tst

-
I have removed the spacing "noise" from the MWE: It is now in this question. –  mforbes Jan 16 '12 at 10:23

Use the starred form \begin{fmfgraph*}.