52 
THE MEDITERRANEAN' KATE KAL1.ST 
ground at intervals. These screens often extend 
for several miles, and are placed so as to cross the 
line of march of the locusts. At the foot of the 
screen, pits about five feet long, 2\ feet wide, and 
three feet deep, were dug, a wooden frame covered 
with zinc was put on the top of the pit so as to 
cover its edges. The locusts on arriving at the 
screen climb up it, but on reaching the top they 
find the strip of slippery wax-cloth, and fall down. 
After trying it over and over again, they turn the 
direction of their march and hop along at the foot 
of the screen, till they presently meet one of the 
pits and fall into it. They climb up the sides to 
get out again, but are met by the smooth zinc 
surface at the edge, and fall back into the pit; 
others come hopping in on top of them, and they 
are soon smothered by each other. 
The system has been maintained by us in. prin- 
ciple, but has been improved in detail. The 
wooden frames have been abandoned, and strips 
of zinc are used instead, which are laid on the 
ground, overlapping the edges of the pits. By 
this means they can be adapted to pits of am 
size, and a great saving is effected in the coast of 
transport, for when a swarm of locusts has been 
destroyed the screens and traps are taken up, 
packed on mules and donkeys, and carried off 
somewhere else. In places where the locusts are 
thick or where they tend to accumulate, such as 
the mouth of a small ravine, very large pits are 
dug, covering a surface of 80 to 100 square feet. 
The locusts come pouring into these like a water- 
fall, and making the same rushing kind of noise. 
When once the locusts begin to fly the traps are 
useless. The period for the locust campaign only 
lasts, therefore, for about six weeks, and every- 
thing depends on an active prosecution of the 
campaign during that period. If large swarm 
escape the whole work has to be gone over again 
the next year. 
It was this consideration that led me to see that 
it was necessary to centralise the management of 
the locust campaign under one head. When each 
commissioner managed it in his own district, 
swarms constantly escaped from one district to 
another, and it was impossible to alot beforehand 
the screens and traps according to the wants of 
each district. Much time was lost in sending 
jpterial from one district to another, I therefore ' 
placed the whole under the Government engineer, 
and as public works were stopped for the time, 
all his organised labour was turned on to the 
work of locust destruction. The result was mo.st 
successful. The number of locusts had been gra- 
dually increasing from 1879 to 1882. That year 
the conduct of the campaign was partially cen- 
tralised, and the numbers of 1882 remained sta- 
tionary. Lu 1883 the operations were thoroughly 
centralised under the Government engineer, and 
when the season opened in 1884 a large decrease 
was perceptible. The destruction was very com- 
! 
| plete that year, and thenceforward it was only 
! necessary to have operations on a minor scale, so 
I as to keep down any swarms that appeared. In 
! 1885 I was able to report that the operations had 
! practically come to a successful conclusion, and it 
j has since been only necessary to prevent the few 
j that annually appear, from increasing so as to 
! make a fresh head again. 
The greatest number which, it was calculated. 
! were destroyed in one year was 195,000 millions in 
! 1883, and the following year 56,000 millions. The 
! estimated number of eggs laid by those that escaped 
i in 1883 was 169.432 millions, and in 1887 it was 
i 1216 millions, of which probably one-half would 
not come to maturity. The extraordinary fecun- 
dity of the locust is such that one pair of locusts 
left uninterruptedly to breed, would in ten years 
reach 2000 millions, even if one-half of the eggs 
| failed to hatch out or were otherwise des- 
i 
i troy eel. 
(To be continued.) 
I Rare occurrence of OPERS APIFERA 
in Malta 
Professor'G. Gulia v as the first to note the oc- 
currence this orchid in Malta, and in his work on 
the orchids of Malta, which was published in the 
columns of '‘Barth 5 ’, he not only designates it as 
being “extremely rare”, but he also observes that 
had found but one single example of it. 
Mr. Armitage, however, informed me that he 
had collected many specimens at One inn ; but 
he still considered it as being one of the rarest of 
the Maltese orchids. 
I was somewhat surprised at this for in April 
last Rear Admiral Lord Walter Kerr, who is con- " 
