The distribution of Psednura pedestris and the northern race of P. musgvavei
was studied in relation to habitat in the heathy vegetation of the sandy coastal plain
near Evans Head, N.S.W. The density of both species was in general very low, corresponding
to an average of only one specimen captured per man-hr; in a few patches
it rose to several times that figure. The distribution of the two species was in the
main mutually exclusive in a mosaic pattern reflecting the mosaic distribution of the
respective preferred habitats, pedestvis occurring on the margins of swamps and musgravei
on somewhat better drained sites. However, at three locations mixed populations were
found in the ecotone between the two habitats. At one of these, which was studied in
detail, the zone of overlap was never wider than 12 m, and the highest density of each
species occurred within a 2-m strip on either side of a median line related to a prominent
habitat feature. The situation is compared and contrasted with that in parapatric
species and races of morabine grasshoppers.