It is important to know how insects take their food

It is important to know how insects take their food

It is important to know how insects take their food, for by knowing this we are often able to destroy insect pests. Some are provided with mouth parts for chewing their food; others have a long tube with which they pierce plants or animals and, like the mosquito, suck their food from the inside. Insects of this latter class cannot of course be harmed by poison on the surface of the leaves on which they feed.

Fig. 141. Beetle
a, larva;
b, pupa;
c, adult;
d, burrow

Source: Agriculture for Beginners