Concentrations in the Local Association

New intermediate band and Hβ observations of members of the delta Lyrae cluster, and previous photometry of the Pleiades, α Persei and M34 clusters, is discussed in connection with the available astrometry. The small age spread shown by the members of these clusters is the same as that for the southern concentrations previously discussed. The limited astrometric data do not support a linear expansion, contraction or differential motions within the association as a whole but may indicate variations in the stream motion at various parts of the association, and this variation may be the effect of differential galactic rotation. A complete sample of bright, northern B-type stars indicates that the association members constitute a third of that population and the HgMn and Ap stars in the sample are represented in the association by the same percentage. (author)