CHAP. CIII. SALICA‘CEH. SA‘LIX. 1483 
moist ground, highly favourable in itself for the growth of osiers, planted it ; 
and, after a few years, the osiers had disappeared, he hardly knew how. 
It was planted a second and even a third time, and the plants always dis- 
appeared. ‘ My attention,” says the writer, “being now strongly drawn 
to the subject, I discovered that which I ought to have perceived half a 
century sooner; namely, that Nématus caprez, favoured by the peculiar lo- 
cality, was the cause of all this devastation. The spot is low, moist, shut 
in by wood, and very near the southern limit of England. The species of 
willow planted was chiefly one of those with broad leaves, woolly underneath 
(probably S. caprea L.). The warmth of the situation, and the nidus for eggs 
afforded by these woolly leaves, were, I presume, the combined cause of the 
insect being so remarkably attracted to this spot. Some of the plants were 
of a species with smooth narrow leaves (probably S. triandra L.): these es- 
caped much longer than the others, but still they did not escape eventually, as 
they were also attacked by another caterpillar. I introduced both red and 
black ants, and put some of the caterpillars into their nests; but the ants 
disregarded them altogether. Having, although thus slowly, ascertained the 
true state of things, the ground was once more cultivated, and was planted 
with apple trees. As there happens to be no insect there which much attacks 
these, they thrive very well. The distance at which apple trees are planted 
is, also, less favourable to the propagation of vermin. I have communicated 
all this detail in order to show the importance to individuals of attending to 
such seemingly trifling matters. Many a plantation, &c., fails in an apparently 
inexplicable manner. A scientific investigation would, in numerous cases, 
disclose the truth, and prevent farther loss. Had a person acquainted with 
entomology been proprietor of this osier ground 50 years since, he would 
speedily have discovered the truth, and might have saved 200/. or more to 
himself and his successors.” (Mag. Nat. Hist., vii. p. 423.) 
The Chrysoméla (Phze‘don) vulgatissima Z. is another species which is 
occasionally injurious to one of the narrow-leaved species of willow. This is 
a pretty little insect, of a shining blue or green colour, and of an oblong-oval 
form, about } in. in length, which is found, during the winter months, in great 
profusion under the loose bark of willows, growing in damp localities. It 
deposits its eggs upon the young leaves; and the larva, when hatched, form 
little associations, feeding together in regular rows, the heads of the second row 
touching the tails of the first. In this manner they proceed from the base 
to the extremity of the leaf, which they soon strip of its parenchyma. They 
then attack the next leaf; and so on, until they are full grown, when they 
descend into the earth, and assume the pupa state; shortly after which they 
undergo the change to their last and perfect form. 
The leaves of some species of willows are also infested with galls, which 
are the production, not of a species of Cynipide, but of one of the Z'enthred{- 
nide (Nématus intércus Panzer Fauna Ins. Germ., 90. fig. 11.; or the 
Tenthrédo sAlicis pentandre Villars). The larve of this insect, instead of 
feeding externally upon the leaves of the willow, is enclosed in a gall, upon the 
substance of which it subsists, and within which it undergoes all its changes. 
Mr. Westwood’s species Nématus gallicola (described by Mr. Stephens, I//ust. 
Brit. Ent., vol. vii. p. 36.), and the Eutra Cynips of Newman (nt. Mag., 
No. 18. p. 260.), also reside in galls; whilst the larve of Nématus sélicis of 
Saint Fargeau, and of the N. capre, are external feeders. 
Among the Lepidéptera, the caterpillars of nearly all the species of moths 
belonging to the genus Certira (puss and kitten moths) feed upon different 
species of willow ; and also, occasionally, the larva of the buff-tip moth (Pygze‘ra 
bucéphala Sfeph.). Brépha Parthénias (the orange underwing) feeds upon 
poplars and willows; and Notodénta ziczac (the pebble prominent moth) upon 
the same: Leioc4mpa dictz‘a and L. dictzdides ( se swallow prominent moths), 
Ptilodéntes palpina (the pale prominent moth), Gastrépactia quercifolia, &c., 
occasionally upon willows; and the larva of Orthdsia dpsilon Steph. beneath 
the bark of old willows and poplars. 
