\begin{table}%t6
\caption{\label{midt}Effective temperatures at the mid-point of each curvilinear quadrilateral representing a~MK~spectral type-luminosity class in the BCD ($\lambda_1, D)$~plane for early type stars.}
\par
\small%\centerline
 {
\begin{tabular}{l|ccr|ccr|ccr|ccr|ccr|ccr}
\hline
\hline
\multicolumn{1}{c}{LC:} & \multicolumn{3}{c|}{V} & \multicolumn{3}{c|}{IV} & \multicolumn{3}{c|}{III} & \multicolumn{3}{c|}{II} & \multicolumn{3}{c|}{Ib} & \multicolumn{3}{c}{Ia}  \ \ \ \ \\
\hline
SpT & $\lambda_1$ & $D$ & $T_{\rm eff}$ & $\lambda_1$ & $D$ & $T_{\rm eff}$ & $\lambda_1$ & $D$ & $T_{\rm eff}$ & $\lambda_1$ & $D$ & $T_{\rm eff}$ & 
$\lambda_1$ & $D$ & $T_{\rm eff}$ & $\lambda_1$ & $D$ & $T_{\rm eff}$   \ \ \ \ \\          
\hline 
 O6-7 & 67.0 & 0.062 & 34640 &  59.4 & 0.060 & 34800 &  54.5 & 0.055 & 35060 &  50.2 & 0.048 & 33970 &  45.9 & 0.040 & 32590 &  37.3 & 0.014 & 29670  \ \ \ \ \\
 O8-9 & 66.1 & 0.075 & 32750 &  58.4 & 0.071 & 33070 &  53.1 & 0.067 & 32460 &  47.9 & 0.061 & 30690 &  43.1 & 0.052 & 28350 &  34.7 & 0.025 & 26040  \ \ \ \ \\
 B0   & 65.1 & 0.094 & 30000 &  56.9 & 0.091 & 29970 &  51.2 & 0.085 & 29070 &  45.0 & 0.077 & 26710 &  39.9 & 0.066 & 24380 &  31.9 & 0.037 & 23890  \ \ \ \ \\
 B1   & 63.5 & 0.121 & 27080 &  54.9 & 0.116 & 26960 &  48.4 & 0.110 & 24880 &  41.5 & 0.099 & 23370 &  36.3 & 0.085 & 22360 &  28.8 & 0.052 & 22020  \ \ \ \ \\
 B2   & 61.5 & 0.160 & 22620 &  52.2 & 0.156 & 22380 &  44.9 & 0.147 & 21740 &  37.5 & 0.127 & 20570 &  32.2 & 0.107 & 19790 &  25.0 & 0.071 & 19310  \ \ \ \ \\
 B3   & 59.7 & 0.203 & 19270 &  49.7 & 0.201 & 19160 &  41.6 & 0.188 & 18900 &  33.5 & 0.160 & 18010 &  28.2 & 0.133 & 17520 &  21.6 & 0.091 & 17140  \ \ \ \ \\
 B4   & 58.8 & 0.235 & 17220 &  48.3 & 0.235 & 17130 &  39.6 & 0.218 & 17310 &  31.1 & 0.184 & 16500 &  25.7 & 0.152 & 16180 &  18.9 & 0.108 & 15660  \ \ \ \ \\
 B5   & 57.9 & 0.269 & 15380 &  47.1 & 0.271 & 15570 &  37.8 & 0.249 & 15890 &  29.0 & 0.211 & 15080 &  23.1 & 0.174 & 14770 &  16.6 & 0.126 & 14460  \ \ \ \ \\
 B6   & 57.7 & 0.302 & 14100 &  46.7 & 0.309 & 14200 &  36.3 & 0.286 & 14530 &  27.1 & 0.241 & 13790 &  20.9 & 0.197 & 13510 &  14.6 & 0.143 & 13560  \ \ \ \ \\
 B7   & 58.1 & 0.333 & 13000 &  47.0 & 0.345 & 13000 &  35.3 & 0.322 & 13460 &  25.7 & 0.273 & 12600 &  19.2 & 0.221 & 12540 &  12.8 & 0.159 & 12800  \ \ \ \ \\
 B8   & 59.1 & 0.363 & 12190 &  47.7 & 0.380 & 12120 &  35.0 & 0.363 & 12380 &  24.8 & 0.306 & 11790 &  17.9 & 0.246 & 11930 &  11.2 & 0.176 & 12280  \ \ \ \ \\
 B9   & 61.5 & 0.406 & 11340 &  49.5 & 0.427 & 11240 &  35.8 & 0.423 & 11240 &  23.9 & 0.362 & 10800 &  16.0 & 0.291 & 11070 &   8.9 & 0.205 & 11720  \ \ \ \ \\
 A0   & 64.8 & 0.448 & 10470 &  52.1 & 0.476 & 10310 &  37.3 & 0.477 & 10350 &  23.5 & 0.431 & 10140 &  14.3 & 0.352 & 10310 &   6.3 & 0.243 & 11010  \ \ \ \ \\
 A1   & 67.4 & 0.476 &  9860 &  54.0 & 0.508 &  9730 &  38.4 & 0.511 &  9820 &  23.7 & 0.478 &  9680 &  13.4 & 0.401 &  9690 &   4.3 & 0.277 & 10440  \ \ \ \ \\
\hline
\end{tabular}}
\medskip
LC = Luminosity class; SpT = spectral type; [$\lambda_1]=\lambda_1-3700$~\AA; $[D] =$ dex.
\end{table}