ti68 EXTRACTS — HORTICULTURE. 
Lacerated and incised wounds of Leaves. — These occur from attacks of 
animals, chiefly of the insect tribes : from hail, and many of the lower animals are 
very destructive to leaves whilst feeding. Some birds seem to do so for amuse- 
ment. The Aphis centunciilaris cuts out portions of leaves, and carries them 
away for its use. Plants frequently become stripped of their foliage in a short 
time by the ravages of the caterpillars, of butterflies and moths, although gener- 
ally they are more sparing in their attacks. These with many others attack most 
plants fit for the food of man. Various methods have been had recourse to for 
the destruction of caterpillars ; washing with tobacco-water and soap, lime-water 
&,c. boiling water has also been tried with success, for those insects which seek the 
ground at particular seasons, unslaked lime laid on, and dug in is advantageous- 
There is what might be termed an appi'oach to a natural cure for this infection, 
in the larvae of an aphidovorous fly which is described and represented by Darwin 
which will also feed on caterpillars. Mr. Elliot's remarks on the subject "when 
the foliage is all off" the trees and bushes, wash them over with the hand-engine to 
clear them off decayed leaves : for this purpose any water will do ; then stir up 
the surface of the earth all round their roots, and lay a little hot lime about 
them to destroy the eggs." Hail is a frequent cause of woimds in leaves ; and 
to ward off these destructive showers, " paragrelis" have been used on the conti- 
nent. The most approved kind consists of a pole of wood from thirty to fifty 
feet long, fixed perpendicularly in the earth, having a brass wire sharpened at the 
point, running from two to three inches above the summit down into the ground. 
These should be planted at the distance of from one to two thousand feet from 
each other. By their influence on the elective state of the atmosphere, the hail 
hail is said to be melted down to snow or rain, the descent of which does com- 
paratively little mischief. It is chiefly in southern climes that these are re- 
quired. Plants receiving wounds in their leaves, must be protected from extremes 
of heat and cold, from too much moisture, and altogether treated more carefully 
than usual, according to the habits of the plants affected. — 
Punctured Wounds of Leaves. Leaves are punctured by various insects 
for two purposes, viz. for the purpose of procuring food, and for O^nposition. 
rmost remarkable insect of the first kind is the Aphis, which attack the under 
ace of the leaves, and young stems, sucking the sap of the plant by inserting 
their curious proboscides. — From these wounds, the leaves become variously 
distorted in shape, generally assuming a blistered appearance, in consequence of 
the irritation from the punctures at particular parts ; and sometimes several of 
these diseased portions may be seen rising nearly half an inch on the surface of 
a leaf otherwise healthy, the concavity of these are found to contain numerous 
Aphides ; such distortions are generally of a whitish or reddish colour, which 
will be explained shortly. On the leaves of the Maple tree, round purple tu- 
mours, with narrow necks, are often found projecting from their upper surface, 
having a small opening leading into them from the under surface, nearly closed, 
however, by a number of morbidly enlarged hairs. These, we believe, to be the 
effects of punctures by the Aphis. Small white tufts are often seen attached to 
the leaves and stems of the larch; these are produced by a brown Aphis, and 
when examined by the microscope, are seen to consist of a bundle of fine fila- 
ments, generally twisted around the animal, and attached to the extremities of 
many ; oval-shaped eggs are also fi-equently seen. Various methods have been 
proposed and practised for the destruction of the Aphis. The most effectual 
