2S6 



ZOOLOGY 



which play such important parts ii? 

 the life of plants also play, in some 

 cases at least, equall}'' important parts 

 in molding the form and structure of 

 animals. 



The Moth. — The Cecropia (Samia 

 cecropia) may be used for laboratory 

 work. Note the general resemblance 

 to the butterfly. Several differences 

 may be noticed, however. The body 

 is much stouter than that of the 

 butterfly. The wings and body ap- 

 pear to have a thicker coating of 

 hairs and scales. Notice also the 

 feathery antennae. What is the rest- 

 ing position of the wings? When you 

 draw the moth, be sure to show the 

 color markings of the wings. 



The Egg. — The eggs, cream- 

 colored and as large as a pin 

 head, are deposited in small 

 clusters on the under side of 

 leaves of the food plant. The 

 young are at first tiny black 

 caterpillars, which later change 

 color to a bluish green, with 

 projections of blue, yellow, and red along the dorsal side. 



Study of Caterpillar. — Captive Cecropias will frequently lay eggs which 

 may be watched in development by placing the young caterpillars in a box 

 with leaves of willow or wild cherry. Watch such an animal, and describe 

 the process of molting. Which end molts first? How do they get out of 

 the old skin ? Is the color of the feeding caterpillars like that of the leaves ? 

 On which side of the leaves do they rest ? How are the leaves held in feed- 

 ing? Are any other parts of the animal besides the jaws used in feeding? 



The Pupal Stage. — Unlike the butterfly, the moth passes the 

 quiescent stage in a case of silk or other material called a cocoon. 

 The cocoons of Cecropia may be found in the fall on willows or 

 alders. Such cocoons found in meadows or fields are usually 

 larger than those found on the hillsides, probably because of a 

 difference in the food supply of the larva which spun the cocoon. 



Study of a Cocoon and Pupa} — Where do you find them, and how are 

 they attached? Of what materials is the cocoon made? An interesting 

 report would be the formation of the cocoon. This may be watched by 



The tiger swallow-tail, showing two forms 

 of females. 



* See Hunter and Valentine, Manual, page 108. 



