CHAPTER XII 

 A CHAPTER ON INSECTS 



INSECTS are so interrelated with general topics that 

 a chapter on insects will serve to further illustrate the 

 progress of zoological study. 



This is the largest group of animals, there being 

 approximately 400,000 species described and classi- 

 fied and there are many not named. From whatever 

 point of view these animals have been studied, they 

 have awakened interest and enthusiasm among 

 naturalists. Those who devote particular attention 

 to this field of study are designated entomologists 

 and the great division of zoology thus set apart is 

 designated entomology. 



From the time of Malpighi (1628-1694) and 

 Swammerdam (1637-1680) insects have been ob- 

 jects of interest and of especial consideration to the 

 minute anatomists. 



In their life histories some insects, as the butter- 

 flies, bees, etc., exhibit in the clearest fashion and in 

 the widest range the phenomena of metamorphosis. 

 Hatching from the egg in a form different from the 



adult many of these animals pass through various 



125 



