A catalogue of more than 900 multiple systems of trapezium type has recently been completed. In constructing the catalogue an attempt was made to exclude optical systems. We study the galactic distribution of trapezia of different spectral types, and we compare it with that of ordinary multiple systems and of visual binaries from the IDS. An estimate is made of the expected number of pseudo-trapezia among each spectral type. This study shows that most of our trapezia are true trapezia and should therefore be young. This conclusion holds for trapezia of all spectral types.