The larvæ burrow into the ground in September to form the chrysalides, hence there should be soil in the vivarium in which they are kept.
THE CHRYSALIS
Observations.—The shape, colour, nature of the covering, the long handle, the wing impressions, the segmental part, the emergence of the adult in May or early June.
What organ of the insect was contained in the "handle" of the chrysalis?
The adult is one of the handsomest of moths, because of its graceful, clear-cut shape and the variegated grays and yellows of its dress. Look on poplar, cotton-wood, plum, and pine trees, and on tobacco plants for relatives of the tomato worm, the large green larvæ whose chrysalis and adult forms resemble those of the tomato worm.
THE CROW
Crows are so plentiful that there will be no difficulty in making observations on the living birds in the free state in spring or summer. (As the crow is a bird that is easily tamed, it may be possible to have a tame crow in the class-room for more careful study of the details of structure.)
Observations.—Describe its attitude when perched, movements of the wings in flight, speed of flight. Why does the crow perch high up in trees? What gives to the crow its swift flight?
Study the various calls of the crow and note the alarm, threat, summons, and expression of fear.
Find the nest and note its position, size, build, materials, eggs, and young. How is the nest concealed? What makes it strong?