ANIMAL STUDIES
SCALE INSECTS
SAN JOSÉ SCALE
Certain districts in Ontario and especially those bordering on Lake Erie have suffered from the ravages of this scale on apple, peach, pear, and other orchard trees. A hand lens should be used in studying these insects, observations being carried on from May to September.
Carefully examine the fruits and twigs of orchard trees for evidences of the presence of the scale, and learn to identify it and to recognize the damages resulting from its attacks.
Observe the almost circular flat scale of a grayish colour and having a minute point projecting upward at its centre. The young insects which emerge from underneath these scales in the spring crawl around for a time, then become stationary, and each one secretes a scale under which it matures. The mature males have two wings but the mature females are wingless. Note the withering of fruit and twigs due to the insects' attacks and the minute openings in the skin of the twig, made by the insertion of the sucking mouth parts.
Describe to the pupils how the insect was transported from Japan to America and how it is now spread on nursery stock. Give a brief account of its destructiveness in the orchards of Essex and Kent.
(Consult Bulletin No. 153, Common Insects Affecting Fruit Trees and Fungus Diseases Affecting Fruit Trees. Bethune & Jarvis, Department of Agriculture, Toronto, free.)
OYSTER-SHELL BARK-LOUSE
This is very common throughout the Province on apple and pear trees. Observe the unhealthy appearance of the leaves of the infested trees, the inferior quality of the fruit, and the gray scales shaped like tiny oyster-shells.
The means of destroying these pests should be discussed. The Bulletins named above give detailed information in reference to spraying and fumigation.
CUTWORMS
(Consult Bulletin 52, Department of Agriculture, Ottawa.)
Cutworms are the larvæ of medium-sized brown moths that fly at night. There are many species of cutworms, all of which are destructive to some forms of plants or grasses, grains, and vegetables.
The larvæ are rather thick, naked, worm-like forms. They burrow into the ground, but emerge at night to feed by cutting through the stems of tender plants or by feeding upon the leaves. For the most effective method of dealing with these refer to what is said on "Combating Garden Pests", Form II.
When a field is known to be infested with cutworms, it is a good plan to spread poisoned clover or cabbage leaves over the ground before the seed is planted.
WHITE GRUBS
White grubs are large, fat, white larvæ of June beetles. These beetles are the well-known large, brown, clumsy beetles that blunder into the house at night in May or June and drop with a thud upon the floor. Three years are spent in the larval form, the grubs living underground and feeding on the roots of plants, especially the roots of grains and grasses.
Since they are found chiefly in fields recently ploughed from grass, they may be held in check by rotation of crops and by fall ploughing, which exposes the larvæ to the winter frosts.
In May or June, when the adults are feeding on the foliage of fruit and shade trees, spraying the trees with London purple is quite effective for destroying the beetles before they have laid their eggs among the roots of the grass.
Hogs destroy many larvæ by rooting in the soil to find them for food.
CRAYFISH
Search for the crayfish in streams and ponds. Why is the crayfish hard to find? Hard to capture?
Obtain a living crayfish from a pond or stream and place it in a jar of water or in an aquarium.
The crayfish should not be placed in an aquarium containing insects and small fish which are to be kept, as it is fierce and voracious.
The pupils should study the living animal, noting its habit of lurking under stones; the sweeping of the water with the feelers; the backward movement in swimming, produced by bending the tail sharply underneath the body; the walking by means of four pairs of legs, the great claws being used to turn the animal; the use of the great claws in seizing prey and holding food near the mouth; the movements of the small appendages under the front part of the animal and the water currents caused by these; the movements of the small appendages under the abdomen of the animal.
FRESHWATER MUSSEL
The freshwater mussel—"clam" as it is usually called by school-boys—may be found in almost any stream.
Place a mussel in the aquarium, and note the opening and closing of the valves of the shell; the hinge connecting the valves; the foot protruding from the shell; the movements by means of the foot; the mantle lobes lining the shell and visible at the open margins; the two siphons at the rear of the animal—water currents may be observed entering the upper and emerging from the lower of these. Infer uses for these currents. Touch the edge of the upper siphon and observe how quickly the shell is closed.
Compare the mussel with the snail as to movements and shell.
Compare also with the oyster and sea clam.
Examine empty shells and notice the pearly layer of the shell, the action of the hinge, and the marks on the shell to which the muscles for closing the shell were attached.
State all the means of protection that you have discovered the animal to possess.