THE MEDITERRANEAN NATURALIST 161 
The other, Ceratitis citriperda McLeay, is a 
species of the same genus, but of the island of 
Mauritius. At all events C. capitata or C. hispanica 
has been already found in Algeria and if the 
assertion of Guerin is correct it is also to be 
found in the Canary Islands (Madeira), and in the 
island of the Azores (St. Michael). 
In Sicily this insect has a preference for the 
fruit of the nectarine, but it does not necessarily 
follow that in other countries it confines its 
attacks to this fruit alone, for in the island of 
Mauritius it attacks ail kinds of fruit, as you 
have had occasion to observe it to do likewise in 
Malta. None of the writers whom I have consulted 
speak of methods of destroying this insect, or of 
ways by which its attacks might be rendered less 
destructive: and as far as I know no steps were 
taken in Sicily to destroy the insects that infested 
the Nectarine. 
However, it is my opinion that great benefit 
would accrue by sacrificing the whole of the fruit 
for a year or two by collecting the oranges before 
they are quite ripe, and as soon as the larvae of 
the insects appears. As a more expeditions method 
I would suggest that the emulsion of Riley should 
be used, and with another emulsion that I warmly 
recommend, and which is prepared as follows : — 
I. Olio di pesce 1 parts 
Solfuro di carbonico 10 „ 
II. Potassa del commercio 2 parts 
Water 10 „ 
Mix the No. I solution with No. II and dilute the 
mixture with 50 times its bulk of water. 
The amount of water may be increased to any 
extent: and the oil and potash may be diminished, 
or the Solfuzo di carbonico may be diminished at 
will, and the emulsion even though rendered wea- 
ker will undoubtedly kill the larvae, and they may 
then be easily washed away either by the rain 
(which is very rare in Malta), or they will disappear 
in time, leaving the oranges free from the pest. 
It would, however, be well to avoid doing this 
during the time when the trees are sprouting or 
blossoming. 
Another substance which can also be used is 
that which is known among chemists as nitro- 
benzine, and commercialy as essence of mirabane; 
this should be diluted with water and then well 
shaken. Cyanide of potassium dissolved in the 
preparation in the proportion of one part to every 
1000 of water could be also tried. 
All of these liquid substances should be applied 
by spraying by means of a pump attacted to a 
tube at the end of which is a rose. It is necessary 
to be careful however, to use a metal tube for the 
oily substances; and for the conducting tube a 
tube of metal must be adopted or a tube of cloth, 
but not of india-rubber. 
The Americans, I think, would not hesitate to 
cover the orange trees with a portable tent beneath 
which they -would develop© the vapour of acido di 
cianidrico, obtained from the decomposition of 
Cyanide of Potassium, when acted on by chloric 
acid. The effect would be no doubt excellent but 
the application of it is very difficult and it is not 
unattended by danger to the operators wffio neglect 
the necessary precautions. 
These then are the methods that I recommed 
to be tried. I now desire for my own informa- 
tion that you may be so good as to furnish me 
with some particulars regarding the range of the 
infection by the Ceratitis, either known or sup- 
posed, in the infected districts, the damages 
caused by it; and to forward me some specimens 
of the orange with the larvae. This could be best 
done I think by sending them in a tin or zinc 
box pierced with air holes; if this could not be 
done it would be sufficient if you were to send 
some pieces of the peel with the larvae, or some 
larvae alone enclosed in either a tin or a zinc tube,” 
Both for these and for other particulars relating 
to the diseases of the Malta Orange we are indebted 
to the courtesy of Mr. E. Taglioferro , the lion. sec. 
of the Malta Orange Commission to whom we noiv 
beg to offer our sincere thanks . . (Ed. Med. Nat.) 
Theories of Mountain Formation. 
BY T. MeLLAED ReADE, C.E., F.G.S., F.K.I.B.A. 
Part V. 
(Conclusion.) 
The relation between volcanic energy and moun- 
tain formation are undoubtedly intimate, yet the 
prevalent ideas on the subject are characterised by 
obscurity. 
Unfortunately phrases so often do duty for 
thought, that it behoves every geological studen: 
to ask himself as he goes along whether the expla- 
nations offered of phenomena are really such, or 
