Postal regulations dictated that comics contain features in addition to the main book title so DuBois contributed series such as "Mabu", "Two Against the Jungle" and "Boy". Issue number 25 in October 1951 saw the debut of the popular series "Brothers of the Spear", which would run for over 25 years and which, in issue 39, would feature the first professional work of brilliant artist Russ Manning.  Manning eventually took over the Tarzan series in November 1965 following Marsh's retirement. The first "Brothers of the Spear" episode occupied a mere six pages, but it launched a serialized story that eventually grew to epic proportions.