\begin{table}%t2 online
%\centering
\par
\caption{\label{tab2}Comparison of previously published spectral classifications.}
\begin{tabular}{lccccccc}
\hline \hline \noalign{\smallskip}
W\# &     \multicolumn{7}{c}{Spectral classification} \\
    & 1966  & 1973 & 1973-4? & 1981 & 1995 &2002  & 2006\\
\hline
 4  &{\em OB}& {\em OB}&--       &G0 Ia & {\em OB} &F2 Ia & $<$G5 Ia \\
 6  &{\em OB}& --       &--       &B1 V  &   --      & B0.5 Iab & --\\
 7  &{\em OB}& {\em OB}&--       &A0 Ia & {\em OB} & B5 Ia & -- \\
 8a &{\em OB}& --       &--       &G0 Ia & {\em OB} & F5 Ia & $<$G5 Ia \\
 9  &{\em OB}& ?       & ?      &Be    & {\em OB} & sgB[e] & $<$G5 Ia \\
10  &{\em OB}& --       &--       &B0 III&   --      & B0.5I+OB & --\\
11  &{\em OB}& --       &--       &B1 II &   --      & B2 Ia & --\\
12a  &{\em OB}&{\em OB} &--       &A2 Ia & {\em OB} & A5 Ia & $<$G5 Ia \\
16a  &{\em OB}&{\em OB} &--       &A2 Ia & {\em OB} & A2 Ia & --\\
20  &{\em M} &{\em M}  &{\em M} &M6 Ia &  --      & $<$M6 I & M5 Ia\\
26  &{\em M} &{\em M}  &{\em M} &M2 Ia & {\em M}  & $<$M6 I & M5-6Ia\\
28  &{\em OB}& --       & --      &B0 II &  --       &B2 Ia & -- \\
31  &{\em OB}& --       & --      &Be    &  --       &B0I+OB & -- \\
32  &{\em OB}&{\em OB} & --      &G5 Ia & {\em OB} &F5 Ia & $<$G5 Ia \\
33  &{\em OB}& --       & --      &B8 Iab& {\em OB} &B5 Ia & --\\
70  &{\em OB}& --       & --      &B8 Iab&  --       & B3 Ia & -- \\
71  &{\em OB}& --       & --      &B8 Iab&  --       & B2.5 Ia & --\\
75  &{\em M}&{\em  M} &{\em M} &--     &  --       & --  & M4 Ia\\
78  &{\em OB}& --       &--       &B1~Ia &  --       & B1 Ia & --\\
237 &{\em M} &{\em  M} &{\em M} &M6    &  --       &$<$M6 I & M3 Ia\\
243 &{\em OB}&{\em OB} &--       &B2Ia  &  --       &A2 Ia & --\\
265 &{\em OB}&{\em OB} &--       &G0 Ia &  --       &F5 Ia & $<$G5 Ia \\
\hline
\end{tabular}
\tablefoot{Note that classifications given in italics have been derived from photometric  data alone, while the 2006 classifications are derived from 2.3~$\mu$m spectroscopy (Mengel \& \mbox{Tacconi-Garman} \cite{mengel}, \cite{mengel08}). Crowther et~al. (\cite{crowther}) provide a comparable table for the WR~population.}
\vspace*{12mm}
\end{table}