251 MR. 8. MOORE ON THE FLORA 
of the late Mr. Bentham * with reference to the comparative 
worthlessness of the pappus does not apply to a country where 
rain and dew, whieh in moister climates so rapidly cause the 
pappus to collapse, are of but rare occurrence, where wind-storms 
frequently prevail, and gentle breezes, sullicient to waft the 
downy plumes over considerable distances, are constantly re- 
curring. Absence of the insects necessary for pollination is 
probably the reason for the extreme scarcity of species belonging 
to orders such as the Epacridex, Stylidez, and (to a certain 
extent) Proteacee—scarcity one would hardly have ventured to 
predict in view of the relative abundance of allied plants in the 
South-west. The flowers of the relatively abundant Luguminos® 
and Myrtacee are, I believe, to a large extent wind-fertilized. 
In fact, after paying considerable attention to the subject, I came 
to the conclusion that self-fertilization almost always obtains in 
the desert. I noticed, indeed, that the flowers of various species 
of Acacia, as also those of Scevola spinescens, were visited by the 
small butterfly Catachrysops biocellata, Feld., in some numbers, 
and the flowers of the latter were also attractive to the handsome 
Delias aganippet, Donov. On only one other occasion did I 
notice insects on flowers. "That was at Gnarlbine, close to per- 
manent water, and here the cloyingly sweet spikes of Grevillea 
nematophylla had attracted quite a number of winged visitors, 
True, ants are abundant, and stragglers from their ranks may 
occasionally be discovered within corollas, though these are by no 
means effectual pollinating agents. But although the frequency 
of insects’ visits may be a matter of great importance to herbs 
with flowers adapted to entomophily, and although shrubs and 
trees with such flowers will stand a better chance of distribution 
in space the more bountiful the supply of insect-life in the 
districts inhabited by them, yet insects are not of such moment 
to shrubs and trees—and shrubs and trees especially abound in 
the desert—because of their perennial habit, and their more com- 
plete exposure to winds, which, by agitating their branches, shake 
* Journ. Linn. Soc., Bot. vol. xiii. (1873) p. 573. 
t Messrs. Butler and Kirby kindiy gave me these determinations. I also 
secured two or three specimens of Junonia vellida, Fabr., a species which settles 
on the ground, never, so far as I saw, on flowers, Besides the above I did not 
see more than two others, and these I failed to secure. Curiously enough, not 
one of my three species figures in the list of Lepidoptera brought down by the 
Elder Expedition. 
