71 
Mr. Sidebotham exhibited specimens of the gall fly, 
Cynips Lignicola, and a number of the galls formed by this 
species. He stated that these galls are very common, 
apparently much more so than a few years ago ; he had 
tried an experiment to ascertain their commercial value, and 
exhibited the comparative strength of colour from them and 
from the blue Aleppo galls. The English galls are much 
lighter, and in the experiment equal weights of each were 
used. The result of the experiments showed that the 
English galls were about two-thirds the value of the foreign 
ones, or, according to the present market value, they would 
be worth about 66s. a hundred weight. In the plantations 
where these galls abound, he thought a man might collect 
easily half a hundred weight in a day, and, on the principle 
that nothing valuable should be wasted, he thought that it 
was very desirable that these galls should be collected and 
made use of. The galls even when in great numbers do not 
appear to injure the trees. The proper time to collect them 
would be the middle of September, when the flies have all 
eaten their way out and laid their eggs for another year’s 
supply. 
A paper on “The Vegetation of Gibraltar during the 
Month of May ” was then read by H. A. Hurst, Esq., 
Treasurer to the Section, 
