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minor details which cannot be touched upon in this paper, although 
a clear understanding of these particularities is of great assistance 
in combating pests. They often constitute the weak point of the 
armour it is meant to penetrate, and serves as a guide in directing 
the attack against them. 
Almost as important as an undertaking of the life history of 
pests is a knowledge of the manner they attack plants when taking 
their food. 
In that respect noxious pests may be considered, irrespective of 
their classification, names, shape, or colour, into two general types: 
biting or chewing insécts and sap-sucking insects. The former are 
often leaf-eaters or bark-nibblers, or, again, wood and fruit borers. 
They are provided with jaws by which they can gnaw the surface 
of the food-plant, and chew it. 
The latter feed on the juices of the inner tissues of the host- 
plant. They are armed with a pointed tube-point beak, which they 
thrust into the tissues of their host-plant, and suck out the sap. 
Of the biting or food-chewing insects, some are :— 
(1) Root-eaters; such as the white worm of the cockchafer; 
the larve of the cicade. 
(2) Others, bark-nibblers; as certain kind of beetles and of 
weevils. 
(3) Some are leaf-eaters; as slugs, caterpillars, saw-flies’ 
larve, the carpenter bee. 
(4) Others injure the bud, the blossom, or the fruit; -as the 
strawberry weevil, the codlin moth. 
Of the sucking insects, in a like manner, some are :— 
(1) Root-sucking insects; as the woolly aphis and phylloxera 
of the vine. 
(2) Others, ordinary bark-sucking insects; as the mealy 
bugs. 
(3) Some leaf and bud or fruit-sucking insects; as the 
rose and the orange aphis, the red and other seales, 
and plant bugs. 
When fighting biting insects, their food plant is best coated 
with substances which will act as internal poisons; whereas, when 
directing the attack against sap-sucking insects, the treatment must 
be such as hurts and kills by direct contact; they are external irri- 
tants, acting from the outside, either closing the breathing pores 
or killing by irritation of the skin. 
Arsenate of Lead is in many respects the most satisfactory 
form of arsenical poison used for combating the first class of in- 
sects named. Take loz. of dry arsenate of lead powder, mix to 
a paste and add to three gallons of water, stirring thoroughly. The 
