QUESTIONS. 91 



constructed within a particular part of the body of the 

 larva, * like a picture upon its canvas, or a piece of em- 

 broidery upon its frame.' The plane of the future star- 

 fish is not even the plane of the larva, but one quite in- 

 dependent of and oblique to it. Strange to tell, the 

 young star does not absorb into itself the body of the 

 larva, which has acted as a nidus for it, but throws it 

 off as so much useless lumber flesh, rods, and all." 



It is a remarkable circumstance in the development of 

 the Echinodermata that, while the adult forms are char- 

 acterized by " radial symmetry," the young " exhibit as 

 complete a ' bilateral symmetry' as annelids or insects." 



QUESTIONS. III. 



1. What is the derivation of " Insecta " ? 



2. Give the definition of this class. 



3. What is the nature of the skeleton ? 



4. What is chitine ? 



5. What is an cxoskeleton ? 



6. What is a somite ? 



7. How many somites are there in the skeleton of an insect, and 



how many of these are assigned to each region of the body? 



8. What are antcnnce, and what is supposed to be their function 



in the Insecta ? 



9. What are the appendages of the thorax ? 



10. Describe the wings. 



11. What is the peculiarity of the anterior pair of wings in the 



beetles ? 



12. What is the structure of the sting of a bee ? 



13. What are ovipositors ? 



14. Enumerate and describe the appendages of the mouth in a 



typical insect ? 



15. What are palpi ? 



16. How are these appendages modified in butterflies and bees? 



17. How are the jaws modified in the bugs and flies ? 



18. Describe the digestive apparatus of a masticating insect. 



19. Describe the circulatory organs in this class. 



20. How does an insect breathe ? 



21. What are trachea ? 



22. What are stiymata ? 



23. Describe the nervous system of insects, 



24. What are compound eyes ? 



