. An introduction to zoology, with directions for practical work (invertebrates). 240 INTRODUCTION TO ZOOLOGY found, mark the leaf on whicli they are, and visit daily. Keep a record of their development, noting dates of hatching, first moult, successive moults, time of dispersal of the brood, date of pupation, etc. In order to find the chrysalis with ease, it may be well to cover the plant, when the caterpillars are large, with a tall but light frame covered with muslin. 2. Bring a few large caterpillars indoors for more detailed study. Examine with a lens, and carefully sketch one of them, ma
. An introduction to zoology, with directions for practical work (invertebrates). 240 INTRODUCTION TO ZOOLOGY found, mark the leaf on whicli they are, and visit daily. Keep a record of their development, noting dates of hatching, first moult, successive moults, time of dispersal of the brood, date of pupation, etc. In order to find the chrysalis with ease, it may be well to cover the plant, when the caterpillars are large, with a tall but light frame covered with muslin. 2. Bring a few large caterpillars indoors for more detailed study. Examine with a lens, and carefully sketch one of them, making clear all the main points in its external structure. Watch the movements of the jaws as the caterpillar feeds. 3. Place a full-fed caterpillar in- side a tall glass cylinder, i Make the cylinder firm by fixing its lower end in a pot of earth, cover the top with a piece of muslin or perforated zinc, shade one side of the cylinder (Fig. 167). The caterpillar will prob- ably begin at once to climb up the glass, and, when so doing, its struc- ture can be very clearly seen, and also the way in which it secretes silk from the spinning-tube, fixing a Fig. zigzag ladder to the glass. When for the caterpillars of moths it reaches the top, it will probably or butterflies. stop and fix itself in preparation for e, A pot of earth ; c, a glass cylinder; pupation. Note the time of fixing, d, a pot of wet sand sunk m the watch the formation of the. silken girdle which supports the body, and in two days' time be on the look-out for the splitting of the skin and the appearance of the chrysalis. 4. Try the effect of changing the environment of caterpillars when about to pupate. Cover the wall of the breeding cage in one case with gold paper, in another with black or red paper, and note the colour of the chrysalis in each case. 5. Put the chrysalids into an airy place, and when the time comes (ie, in two or three weeks if it is the first brood of the year, or the fol
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