Teachers' Leaflet. 547 



Note that it has a coarse covering outside and a smooth silken 

 lining and that between the two there is a loose filling of silk. Explain 

 that this is a device for protecting the insects both from the changes 

 of temperature and from dampness ; and it also makes it more difficult 

 for a bird to tear the cocoon apart. Note that at the end of the cocoon 

 where the moth issues, the silk is not woven across but is put on length- 

 wise so that the end of the cocoon will open like a valve. Explain that 

 this was done by the caterpillar so that the moth could get out more 

 easily. At the same time it is well to explain that this is instinct and 

 not forethought. See Vol. of Cornell Nature-Study, p. 168. 



LESSON CXV. 

 the eggs. 



Purpose. — To call attention to the appearance of the eggs and to 

 the provision which the mother moth makes for her young. 



The mother cecropia if allowed her freedom is very careful to lay 

 her eggs upon a plant or tree the leaves of which afford acceptable food 

 for her young. These trees are usually apple, plum or wild cherry. 

 The eggs are cream white, about as large as the head of an ordinary 

 pin, and they are laid in small clusters in short rows, sometimes on the 

 upper surface and sometimes on the lower surface of a leaf. If some 

 of the eggs are kept out-of-doors and some are brought in the house 

 the pupils will notice that those in the warm temperature hatch sooner. 

 Explain the benefit of this habit to the caterpillar, for if the weather is 

 very cold in the early spring, the leaves do not grow rapidly and, there- 

 fore, it is better for a caterpillar not to hatch so soon. If the moth 

 reared in the schoolroom lays the eggs, they are likely to " cave in " and 

 not hatch, because they are not fertilized. 



LESSON CXVI. 



the caterpillar. 



Purpose. — To interest the pupil in the life-history of the moth of the 

 cecropia. 



The chances are against being able to study the caterpillar during the school 

 year. If you watch the hatching of the eggs in the spring the young caterpillars 

 may attain part of their growth before the middle of June. Occasionally a belated 

 caterpillar in the last stages may be found in September and if so this should be 

 a mine of wealth in the nature-study class, for it may be observed building its 

 cocoon. If the children are familiar with the moth the cocoon and the eggs, it 

 may be well to tell them the story of the caterpillar something as follows: From 

 the egg hatches a tiny caterpillar about one-fourth of an inch long, very dark and 

 with six spiny warts on each segment. It eats and eats for four days, using the 

 leaf on which it was born for food; then its skeleton skin becomes too tight and 

 finally bursts and is pushed ofif, and new skin is formed under the old one, which is 

 elastic at first and gives the little fellow plenty of room. This skeleton skin looks 



