  In this paper, we study maps from reducible curves $f : C \cup_\Gamma D \to
\mathbb{P}^r$. We restrict our attention to two cases: first, when $f|_D$
factors through a hyperplane $H$ and $f|_C$ is transverse to $H$; and second,
when $r = 3$. Degeneration to stable maps of this type have played a crucial
role in works of Hartshorne, Ballico, and others, on special cases of the
maximal rank conjecture. However, the general problem of studying when such
stable maps with specified combinatorial types exist remains open. Here, we
give criteria for such Brill--Noether curves of this first type to exist, of
specified degree $d$ and genus $g$, such that $f|_C$ is of specified degree
$d'$ and genus $g'$. We also give criteria, sharpening earlier results of the
author, for the existence of Brill--Noether space curves of specified
combinatorial types.
  As explained in arXiv:1809.05980, these results play a key role in the
author's proof of the Maximal Rank Conjecture.
