100 INSECTS. 



placing like parts together, study them comparatively, to 

 note the diverse modifications of parts that are homologous. 



6. Bring together, for comparative study, the drawings 

 that have been made of entire insects, and note which 

 body segments are specialized in each. Dissection of these 

 insects would have revealed a corresponding diversity in 

 the development of the internal organs ; and the study of 

 all shows one plan of structure, with great variety in the 

 details of its execution. 



7. Study the drawings to ascertain whether the modifi- 

 cations of wings and legs, and other organs, is always in 

 harmony with the habits of the insect. Does the insect do 

 with its locomotive appendages just what they seem fitted 

 for doing ? Could you not tell, by looking at an unknown 

 insect, whether it spends the greater part of its time 

 afoot, or a-flying? 



'8. Special organs of touch (antennae and palpi), and 

 special organs of sight (eyes and ocelli), are evident in the 

 insects studied. In the adult dragon fly, the eyes are 

 specialized, and the touch organs reduced. Which of 

 these two senses is probably more serviceable to the 

 dragon fly, and why? Why are the eyes reduced, and 

 the tactile organs specialized, in some beetles ? 



9. Take some unfamiliar insect collected and killed by 

 another person, and after studying carefully the devel- 

 opment of its parts, and their probable uses, write out 

 some inferences not guesses, but inferences from facts 

 of structure observed as to the habits of the insect, 

 particularly as to its habits of feeding and of locomo- 

 tion. Then compare your inferences with the facts as 

 you can learn them from later observations, on the insect 

 alive, or from reading. 



10. Compare the wings of a grasshopper, bug, and bee- 

 tle. Observe that in the first two the fore wings are pro- 

 tective coverings, as well as organs of flight. And do not 



