xl The Transactions of the South African Philosophical Society 
The opinion was expressed that possibly Bush fires might be caused 
by broken glass lying on the grass. 
The Rev. D. P. FAuRE exhibited a bright yellow Disa which had been 
found on the Twelve Apostles. Orange-coloured ones had been found 
at Ceres, but one like this had not been seen before. 
Dr. MARLOTH gave the following explanation : 
‘Many wild plants with coloured flowers sometimes produce white 
flowers, and gardeners have fixed many such varieties by cultivation. 
The blue Agapanthus and several species of red and purple Watsonias 
are found with white flowers. This is due to the absence of the blue or 
red pigment in the cells of the petals. The colour of Disa uniflora 
as well as Disa ferruginea is, however, not produced by a single 
pigment but by two, namely, a red pigment which is dissolved in the 
sap, and a yellow one in the form of granules ; hence those parts of the 
flower which do not contain the red pigment appear yellow, and with- 
out examining the present case one can easily understand why it is 
yellow.’ Dr. Marloth had found a few specimens of Disa ferruginea 
with flowers of the same pale-yellow colour as the present one, a fact 
which confirms the explanation given.* 
Mr. Bouus exhibited four orchids which four days ago were growing 
near Komgha. He also exhibited drawings of recent accessions to our 
knowledge of orchids—one a rare orchid found by Schlechter at 
Swellendam. It had only been found previously by Burchell in 1815, 
and then. by Dr. Kraus in 1838, | 
Mr. Bouus also referred to an incident that occurred in his garden 
a few days ago, illustrating the habit of sphex, viz., stinging and 
paralyzing any insect in which it wishes to deposit its eggs. A 
large sphex was dragging a tarantula, and a number of small flies 
were surrounding it. Every time the sphex went to look out the 
way, the flies attacked the spider, then the sphex returned and drove 
the flies away. 
Mr. PERINGUEY said formic acid was the chief agent in the paralyz- 
ing action of the sphex. The interesting point in this case was that 
the sphex must have had a hard and dangerous fight to overcome the 
spider, yet the flies were laying eggs in the body of the spider when 
they got the chance. The eggs of the flies would mature first, and no 
sphex would result. 
Dr. MARLOTH exhibited a specimen of Disa uniflora, with two flowers 
on, which, put alongside one another, measured nine inches. 
The undermentioned presents were announced, and the thanks of the 
’ Society voted to the donors: 
* A few days after this meeting Dr. Marloth found on Table Mountain a specimen 
of Disa graminifolia with one pure white flower instead of the normal purple. 
