SYNOPSIS. 



INSECTA. 



[Figures refer to pages.] 



Caloptenus femoratus, a typical form, 8. Locusts and grass- 

 hoppers, 8; distinguishing characteristics, 9. Directions for col- 

 lecting material for class-work, 9, 10. General characters of the 

 locust, 10. External skeleton, lO; colors of skeleton, Hagen's 

 and Minot's views, 1 1. Body described as a whole, 12; seg- 

 mentation, 12; use of term " Articulata," 12. Arthropods and 

 Worms contrasted, 12. Parts of body described, 13; head, 13; 

 motion of head, 13. Characters of prothorax, 13, 14; meso- 

 thorax, 15; metathorax, 16; primitive and secondary sutures, 

 16; origin of sutures, 16; causes of concentration of thorax, 

 16, 17. Junction between thorax and abdomen, 17; sessile and 

 pedunculated abdomen, 17; characters of abdomen of male, 18; 

 of female, 18; "tympanal organs," 19; Minot's observations, 

 19. Sense organs of head, 19; compound and simple eyes, 19, 

 20; views on the structure and physiology of the organs of 

 sight, 20-22. Appendages, structure and functions of antennae, 

 22; experiments of Trouvelot, Packard, Lubbock, Meyer, 

 Plateau, 22, 23. Biting mouth parts, 24; ravages of locusts, 

 24; functions of palpi, 25; Plateau's experiments, 25, 26; palpi 

 of dragon-flies as useful organs, 26. Inference in regard to 

 cephalic rings, 27; concentration of sense organs in the head 

 correlated with concentration of nervous system, 27. Appen- 

 dages of thorax, 27. Structure of hind legs correlated with 

 habit of leaping, 28. Power of adaptation possessed by animals, 

 28. Structure of wings, 29, significance of term " Orthoptera," 

 correspondence between size of wings and thoracic rings, 30. 

 Origin of wings, 30, 31. Aerial locomotion illustrated by an arti- 



