PROBLEM 11 37 



a. Eggs 



Method and Observations. In the field look on the under side 

 of leaves for tiny ovoid structures (eggs) of moths and butterflies. 

 The eggs of the cabbage butterfly may be found at almost any 

 time on the under side of cabbage leaves. 



Conclusion. Why are the eggs laid on the under side of 

 certain leaves? 



b. Larva or Caterpillar 



Observations. Note, that, besides true jointed legs, the 

 caterpillar has others called prolegs. How many true legs are 

 there and where are they located ? How many prolegs are there ? 



Locate the spiracles or breathing holes. Remember where 

 they are located on an adult insect. 



Watch the caterpillar when it feeds. What kind of mouth 

 parts does it have? Might it do damage to plants? How? 



Conclusion. 1. Is a caterpillar a worm? (Look in your bi- 

 ology for the characteristics of worms.) 



2. How might the larvae of moths or butterflies be of economic 

 importance ? 



c. Pupa 



Materials. Cocoons of several species of moths with twigs or 

 other parts attached should be furnished for this exercise. 



NOTE. Moths spin a cocoon for themselves at this stage. Butterflies spin no 

 cocoon but form a chrysalis. 



Observations. Where do you find the cocoon or chrysalis? 



Of what does the cocoon seem to be composed ? (The cocoon of 

 the Cecropia is excellent for this purpose.) 



In a chrysalis locate by means of the body markings the head, 

 antennae or feelers, eyes, wings, legs, and spiracles. Are all the 

 parts of an adult present? 



Open a cocoon. What do you find inside ? How do you explain 

 this? 



Conclusion. Making use of all the knowledge you have 

 gained, write a brief description of the pupal stage of an insect and 

 tell of what use this stage might be to the insect. Remember 

 where you find these stages. 



