theories, which is also seen clearly in the ( c$_{1}$, c$_{2}$ ) representation (Fig. 3b). In the ( x, p ∗ ) representation (Fig. 3c) both theories predict a region of composition values for which the spinodal lies inside the biphasic region. For illustration of the re-entrant part of the phase diagram one should keep a constant fluid composition near x = 0 . 6 but increases the pressure from p ∗ = 0 to p ∗ = 1: the state changes from I → I + N$_{2}$ → N → I + N$_{2}$ → N where N$_{2}$ is a nematic phase composed mostly of particles of species 2. The order parameters along the nematic branch of the binodal are shown in Fig. 3d. S$_{1}$ remains lower than S$_{2}$ for a given composition, again suggesting that the particles of species 2 are more ordered than those of species 1 at coexistence. When the re-entrant feature occurs at about x = 0 . 6, S$_{1}$ , S$_{2}$ and S$_{tot}$ drop sharply. The difference between S$_{1}$ and S$_{2}$ along the nematic branch of the binodal has become much larger than for λ = 1 . 4. In Fig. 4 we present the phase diagrams for λ = 2. The most striking feature after increasing the size ratio to λ = 2 is the stable N - N coexistence region. For FMT the ( c$_{1}$, c$_{2}$ ) representation (Fig. 4a) reveals that this region is in the form of an almost symmetric hump suggesting that the fractionation between the two distinct nematic phases becomes less with increasing density. There is also a triple point which is in the form of a triangle connecting a low composition isotropic phase, a nematic phase composed mostly of particles of species 1 ( N$_{1}$ ) and a nematic phase composed mostly of particles of species 2 ( N$_{2}$ ). The symmetric N - N coexistence region is more clearly seen in the ( x, p ∗ ) representation (Fig. 4c) between x just greater than 0 and x = 0 . 45 ending in a critical point at ( x, p ∗ ) = (0 . 19 , 2 . 72). In the ( x, p ∗ ) representation the triple point collapses onto a line and the pressure at the triple point is approximately p ∗ = 1 . 75. The I - N biphasic region has become increasingly pronounced. The topology of the phase diagrams is the same as that obtained in Onsager theory results (Fig. 4b and Fig. 4d). The re-entrant feature obtained from Onsager theory is less pronounced than in FMT. The N - N phase separation occurs over a larger range of composition values (up to near x = 0 . 5) and the triple point occurs at approximately a unit of reduced pressure higher than the triple point predicted by FMT, nevertheless, as we emphasise, the topologies predicted by both theories are the same. The I - N spinodal enters the biphasic region for both theories. We postpone the discussion of the order parameters for λ = 2 and higher size ratios until the end of this section. In Fig. 5 we show the results for λ = 2 . 5. There is N - N demixing in the system, as is observed for λ = 2, however there is a big difference in the toplogy of the phase diagrams in 19