Linepithema is the correct
generic name for the New World ants formerly placed in Iridomyrmex.
Iridomyrmex has been shown to be an exclusively Australian
genus (Shattuck, 1992).
With the removal of pruinosus
from "Iridomyrmex" to Forelius (Snelling
and George, 1979; Wheeler and Wheeler, 1986) we are left with but
one species of Linepithema in California, L. humile (Mayr),
the Argentine ant. This introduced species seems
to be unable to establish itself in natural habitats, and is, therefore,
an urban ant. In the deserts it does not seem to do at all well.
We have seen occasional specimens from Palm Springs, Indio, Brawley
and El Centro (Map 8). During our own visits to these and other
desert communities we have not seen the ant and consider that it
is not firmly established. In all probability it is repeatedly introduced
from coastal populations.