A LESSON IN CLASSIFICATION. 101 



fail to note, that, just in proportion as they become service- 

 able for protection, they become useless for flight. This 

 is a good illustration of the universal law, that precise 

 adaptation to one thing brings limitations in other things. 

 Observe, also, that with the decrease in usefulness of 

 the fore wings, there is an increase in size of the hind 

 wings, that the hind wings become disproportionately 

 large, and have to be folded when at rest. Compare their 

 several methods of folding. 



11. Which of the insects studied have complete, which 

 incomplete, metamorphoses ? 



12. Which are injurious to vegetation, and during what 

 stage of metamorphosis are they most injurious ? Which 

 are directly beneficial to man? 



13. Which eat different food in different stages of life ? 



14. Which are most musical (or noisy, if you please), 

 and by what means do such produce their sounds ? 



15. Mention examples of the dependence of insects 

 upon mimicry for protection. Which of the insects 

 studied show the highest instincts in the care of their 

 young? In the construction of their nests? 



A LESSON IN CLASSIFICATION. 1 



Have a good supply of butterfly specimens on hand, 

 before beginning the following work; the more different 

 kinds, the better. 



1 This lesson outlines a simple and natural introductory method which 

 has proved very serviceable. First steps in classification may be illus- 

 trated with other insects as well as with butterflies, perhaps better with 

 some others. The teacher will probably find 'this method most service- 

 able when applied in the group with which he is best acquainted. In 

 applying the method to butterflies, the groups as laid out in the works 

 most commonly found in school libraries have been recognized here as 

 sufficiently answering the purpose of this lesson. Recent changes and 

 improvements in the classification of butterflies may be introduced when 

 they have made their way into available literature- 



