60. 
S.A* X.V1., VOL. XV. 
A ales on Caladniia Latijolia. march 27tji. 19.'4. 
shapes, tremulous labclla and bright colours in attracting insect 
visitors. Xo doubt the insect, when once persuaded into visiting 
the flower, would find some recompense for its trouble, even 
though its hopes of obtaining pollen from the yellow glands at 
the base of the column are vain and the glitter of the calli in the 
label!um is no warrant that thev contain nectar. Perhaps this 
open invitation to all insects is the cause of the large number of 
hybrid forms which we find among the larger species of Caladniia. 
At this stage it might be interesting to quote some notes on 
tire senses of insects by 11. Womersley, the entomologist: of the 
S.A. Museum. In an article in the “Advertiser." he states that 
lire honey-bee can distinguish blue but is blind to red; it can dis¬ 
tinguish vellow, but is unable to differentiate it from orange or 
yellow-green; similarly they turn to blue-violet or purple alike. 
When we couple to this imperfect colour sense the well-known 
fact that insects perceive movement much more clearly than 
they do form, we no longer wonder at the frequency of natural 
hybridism among the large-flowered Caladcnias which strangely 
enough wear the colours that bees would most likeh misjudge, 
nameK reds and \ ellow-greens. 
In main orchids wc find some (actor which has a limiting 
effect on tlie type and size ol insect visiting it. \\ c are remind¬ 
ed of that native of Madagascar. Angraecum sesquipedah\ which 
has a nectarv of enormous length and can be visited only by 
moths with very long proboscides. In one ol the orchids men¬ 
tioned above, namely Caladniia defnnnis, the size of the insect is 
definitely limited. An insect too large would be unable to enter 
far enough to reach the desired tissues while an insect too small 
would not be strong enough to lever the labellum outwards to 
enable it to enter. Thus we find in many cases certain species 
of insects have become the regular associates ol certain orchids. 
Certainly there are exceptions, such as the case of the large 
Caladniia species. An article by K. K. Pescott in the September 
1^33 issue of the \ ictorian Naturalist has a very interesting 
paragraph on some such hybrid forms. Kvcn wdiile writing 
these notes 1 found a flower which was almost, certainly a cross 
between Caladniia reticulata and C. dilatata. 
All this suggests that various insects are concerned with 
the pollination of these larger species of Caladniia and that, al¬ 
though each may tavour one species of orchid, it is easily lured 
away from that form b\ the bright colours, or rather the simil¬ 
arity of colours, of another large species. 
It is with a feeling ol relief that we turn to a sr.ecies in which 
wc can find a definite item ol attraction for insect visitors and a 
lowci which by its shape is able to select with a fair degree of 
