The house wren may be studied as a type. Observe its brownish colour, faintly mottled; its small size and energetic movements, its tail turned nearly vertically upward. Observe and report on other wrens, noting any differences. CABBAGE-BUTTERFLY Have a plant of wild mustard or a cabbage growing in a pot. In June, have the pupils, by means of the insect net, catch a number of the white butterflies, the adults of the cabbage-worm. Place the butterflies in jars or bottles and observe them. Make drawings of them. Direct the attention of the pupils to the difference between the wings of the male and those of the female. The former has only one dark spot on the front wing, while the female has two spots on this wing. Release the males and put the females in a vivarium with the potted plant. (A pasteboard box, with a large piece cut out and the opening covered with gauze, makes a good substitute for a vivarium in this case.) Observe the laying of the eggs. How many are placed at one spot? How are the eggs protected? The eggs may be gathered from the cabbage plants in the garden. Observe and record the hatching of the tiny worm, its feeding, growth, forming of chrysalis, development into adult. Frequently little yellow silken cocoons are found in vivaria where cabbage-worms are kept; these are cocoons of a parasite (braconid) that infests the worm. Because of the ease with which the cabbage-butterfly may be obtained and the rapidity of its development in the various stages, it is very suitable as a type for the study of metamorphosis. The sulphur, or puddler (called by the latter name because of its habit of settling in groups around the edges of the water holes), is also a suitable type. The larvae in this case must be fed on clover. THE TUSSOCK-MOTH Begin the study of this insect in June and July by observing the larvae feeding on the foliage of the horse-chestnut and other shade trees, and direct attention to their destructiveness. In observing the larvae, note the size, movements, legs, colour, coral red head, tufts of hair on the back, and the three long plumes. Watch the birds among the trees to discover whether they eat the larvae. Of what use are the tufts of hair? Do the larvae feed by biting or by sucking? Describe the damage done by the larvae. Collect a number of these larvae and place them in the vivarium with some twigs of horse-chestnut. Observe the spinning of the cocoon and, about two weeks later, look for the emergence of the adult moths. Observe the two kinds of insects. Describe each. Are there any differences in the cocoons from which they emerge? Which form of insect places the egg mass and is therefore the female? Note the number and shape of the eggs and how they are protected. The female moths have no wings and do not move far from the cocoons from which they emerge, while the males have the power of flight.