INDIRECT INJURIES CAUSED BY INSECTS. 101 
If the beer-drinker be thus interested in the history of these animals, 
equally so is the drinker of tea. Indeed sugar is an article so universally 
useful and agreeable, that what concerns the cane that produces it seems 
to concern every one. ‘This also affords a tempting-food to insects. The 
caterpillar of a white moth, called the borer, for destroying which a gold 
medal has been long offered by the Society of Arts, is, in this respect, a 
great nuisance, boring into the centre of the stem, and often destroying a 
great proportion of the crop. This insect (for his essay on which he 
received the offered medal) has been described by the Rey. L. Guilding, in 
the Transactions of the Society of Arts (xlvi. 143.), under the name of Diatrea 
Sacchari, which, however, Mr. Westwood conceives is identical with 
Phalena saccharalis Fab.* An ant also (Formica analis) makes a lodgment 
in the interior of the sugar-cane in Guinea, and destroys it.—Another 
species of the latter genus does not devour it, and it therefore improperly 
called Formica saccharivora by Linné ; but, by making its nest for shelter 
under the roots, so injures the plants that they become unhealthy and un- 
productive. These insects about seventy years ago appeared in such 
infinite hosts in the island of Granada, as to put a stop to the cultivation 
of this plant ; and a reward of 20,000/. was offered to any one who should 
discover an effectual mode of destroying them. Their numbers were in- 
credible. They descended from the hills like torrents, and the plantations, 
as well as every path and road for miles, were filled with them. Many 
domestic quadrupeds perished in consequence of this plague. ats, mice, 
and reptiles of every kind became an easy prey to them: and even the 
birds, which they attacked whenever they alighted on the ground in search 
of food, were so harassed as to be at length unable to resist them. Streams 
of water opposed only a temporary obstacle to their progress, the foremost 
rushing blindly on to certain death, and fresh armies instantly following, 
till a bank was formed of the carcases of those that were drowned sufli- 
cient to dam up the waters, and allow the main body to pass over in safety 
below. Even the all-devouring element of fire was tried in vain. When 
lighted to arrest their route, they rushed into the blaze in such myriads of 
of entomology. Led by their old prejudices of the fly being produced by cold 
winds, &c., they do nothing towards its destruction, though if aware of the way in 
which it is generated (as lately explained), and that by killing each female as it 
appears early in the spring, they would prevent the birth not of thousands but of 
millions of aphides; were they to take measures for thus lessening the number of 
their destructive enemy, they might in great measure secure themselves from its 
attacks. The aphides being so soft are killed with the slightest pressure; so that it 
is merely necessary to rub an infested leaf between the thumb and fingers, with a 
force quite insufficient to injure its texture, to destroy every aphis upon it; and, from 
experiments which I eave made in the hop-grounds of Worcestershire when at 
Malvern in 1888, I am persuaded that every leaf of each hop plant might be thus 
cleared of the female aphides, first attacking it in spring, by women or children 
mounted on step-ladders for this purpose, in ten minutes or less; so that six plants 
being cleared per hour, sixty might be cleared per day at an expense of a shilling 
for labour, and the first cost of a few step-ladders; and by repeating the operation 
every week or fortnight, there can be no doubt a hop plantation might be effectually 
preserved from the fly; as it might earlier in the spring from the flea (/altica con~ 
cinna), by shaking them into a kind of wide and deep sieve (divided into two halves 
with a circular space for the hop poles and hop stems) with a linen bottom and bag 
for preventing them from jumping out again. 
1 Westwood, Modern Classif: of Ins. ii. 411. 
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