176 A GUIDE FOR THE STUDY OF ANIMALS 



4. Postembryonic Development or Metamorphosis of a Butterfly 



, . . , or Moth 



Materials. ■ 



The eggs, caterpillars, pupae, cocoons, and adult of some 

 moth or similar stages of a butterfly. 



Definitions. 



Prolegs, short, unsegmented appendages found in the 

 larva. 



Caterpillar, the larva of a moth or butterfly. 



Spiracles, openings into the trachse or breathing tubes. 



Tubercles, knob-like projections. 



Chrysalis, the pupa stage of a butterfly. 



Cocoons, the covering spun by the larva before changing 

 to the pupa. 



Observations. 



X. State the color and appearance of the larva. If tu- 

 bercles or spines are present, state where. Where are the 

 spiracles .■' How do you distinguish the head, thorax, and 

 abdomen in the case of the caterpillar .' 



2. What kind of mouth parts has the caterpillar "i 



3. How many prolegs has the caterpillar .' Of what 

 use are they ? 



How does the number of prolegs differ from that of the caterpillar in 

 the case of the grub ? maggot ? currant worm ? 



4. What is the advantage of the cocoon ? What is its 

 color, appearance, and material ? Is it composed of a 

 tough substance, or is it easily torn ? Where are cocoons 

 found out of doors ? Where would you look for chrysa- 

 lids ? (Explain differences in locations.) 



Describe the cocoons of tussock moth, clothes moth, leaf roller. 



5. What is the difference between a Cecropia cocoon 

 which contains a living pupa and one that has been parasit- 



