  For a natural number $N\geq 2$ and a real $\alpha$ such that $0 < \alpha \leq
\sqrt{N}-1$, we define $I_\alpha:=[\alpha,\alpha+1]$ and
$I_\alpha^-:=[\alpha,\alpha+1)$ and investigate the continued fraction map
$T_\alpha:I_\alpha \to I_\alpha^-$, which is defined as $T_\alpha(x):=
N/x-d(x),$ where $d(x):=\left \lfloor N/x -\alpha\right \rfloor$. For all
natural $N \geq 7$, for certain values of $\alpha$, open intervals $(a,b)
\subset I_\alpha$ exist such that for almost every $x \in I_{\alpha}$ there is
an natural number $n_0$ for which $T_\alpha^n(x) \notin (a,b)$ for all $n\geq
n_0$. These \emph{gaps} $(a,b)$ are investigated in the square
$\Upsilon_\alpha:=I_\alpha \times I_\alpha^-$, where the \emph{orbits}
$T_\alpha^k(x), k=0,1,2,\ldots$ of numbers $x \in I_\alpha$ are represented as
cobwebs. The squares $\Upsilon_\alpha$ are the union of \emph{fundamental
regions}, which are related to the cylinder sets of the map $T_\alpha$,
according to the finitely many values of $d$ in $T_\alpha$. In this paper some
clear conditions are found under which $I_\alpha$ is gapless. When $I_\alpha$
consists of at least five cylinder sets, it is always gapless. In the case of
four cylinder sets there are usually no gaps, except for the rare cases that
there is one, very wide gap. Gaplessness in the case of two or three cylinder
sets depends on the position of the endpoints of $I_\alpha$ with regard to the
fixed points of $I_\alpha$ under $T_\alpha$.
