142 
THE APHIS VASTATOR. 
ordinary fecundity, observes,* " Such being 
their powers of propagation, and the voracity 
with which they attack the respective plants 
they feed upon (and few there be that are ex- 
empt from them), if they had not natural 
enemies to subdue them, all the efforts of man 
would be unavailing, and they would soon pro- 
duce universal desolation." Curtis remarks, f 
" The mischief that follows from the presence 
of the aphides arises from their thrusting a 
hollow proboscis into the leaf or stalk of a 
plant, through which they imbibe the juices, 
thus supporting themselves at the expense of 
the plant ; and by thus draining it of its due 
nourishment it soon becomes exhausted, droops, 
and often dies, when the number of the aphides 
is very great." In another place we find it 
stated t that " were they not eagerly sought 
for by many other creatures, they would be- 
come more destructive to- the whole vegetable 
creation than any other race of insects what- 
ever." Again we read,§ that " many species 
of aphis commit most destructive depredations. 
During the summer of 1833 the cabbage and 
turnip crops in Kent were much injured and 
often destroyed by countless swarms of A. 
brassicoe" Loudon speaks of them || as being 
most " universal depredators of vegetables." 
This is evidence enough of the power of these 
insects over vegetable life ; and the main diffi- 
culty in accepting Mr. Smee's theory is, that 
there should result from the attacks of the 
insect, a tainted existence, instead of entire 
destruction, in the case of such as were at- 
tacked. This seems in some degree to favour 
the views of those who consider that thj con- 
stitution of the plant is impaired by high cul- 
tivation. Probably a combination of the causes 
which have been assigned furnish a better ex- 
planation of the origin of the disease than 
either of them separately. In fact, it is not 
difficult to believe that a weakened constitution 
in the plant, resulting from excessive, high, 
(not lengthened) cultivation — that mode of 
6 
t 3 
cultivation, too, somewhat unnatural — accom- 
panied by a morbid condition of the atmosphere, 
the latter condition also favouring the pro- 
duction, and aiding the attacks, of parasitical 
insects and fungi, would produce such a result 
as we have witnessed in the case of the potato. 
We are, nevertheless, aware that there are facts 
which viewed singly have a bearing against 
every one of these assumed causes. 
It is also fair to state, that by those persons 
in this country who have chiefly supported the 
insect theoiy, very different kinds of insects 
have been pointed out as the cause ; and we 
believe Mr. Smee was the first who charged 
the mischief to an aphis. 
The engraving at the head of this article 
represents the aphis in its larva (I), pupa (2), 
and winged (3) state, all considerably magni- 
fied. The detailed figures** here introduced 
* Practical Gardener (ed. 1845), p. 326. 
t Gardener's Chronicle, 1842, p. 4. 
X Dr. Gregory's Dictionary of Arts and Sciences, 
i. 22. 
§ Penny Cyclopaedia, art. Aphis. 
are more highly magnified ; theyrepresent (1), 
the under surface of the vastator, showing the 
rostrum in its natural posture, the lancets 
being withdrawn, and consequently invisible ; 
(2) the rostrum separate, the lancets with- 
drawn; (3) the rostrum separate, the lancets 
projecting from the apex ; (4) the rostrum 
separate, the lancets projecting, and showing 
their three component parts ; and (5) the 
rostrum, showing the lancets partly dislocated 
irom the groove which is situated on its in- 
ferior surface. 
As to remedies, Mr. Smee sums up what he 
proposes as follows : — 
The best means of destroying the cause is 
to pick off the insect when we desire to pro- 
tect a single plant. To pull off affected leaves, 
or to sprinkle them with quicklime, when we 
wish to protect a larger number of plants. We 
should endeavour to get our produce ripe at 
|| Encyclopaedia of Gardening (ed. 1834), p. 692. 
* :f From the United Gardeners' and Land Stewards' 
Journal, 1847, p. 38. 
