GENERATION, SEX AND ONTOGENY 



235 



or the animal is said to undergo or to show metamorphosis m . 

 its develojnnent. 



This metamorphosis is faniihar to all in insects; to zoologists, 

 it is familiar among numerous other lands of animals. Fi'j. i:iS 



Fig, 138. — Metamorphosis of the Monardi ])utterny, ,1 misia plcxippus: a, IOkk; b, lan-a; 



c, pupa; (/, imago, or ailult. 



shows the different stages in the nictaniorpliie dcvcloiimriit 

 of the common hirge red-l:)rown milkweed butterfly, AfUKsia 

 plexippiis. From the egg hatches a crawling, wormlike larva, 

 wingless, without comj^ound eyes, and with strong jaws anil 

 other mouth parts fitted for l)iling. This creature develops 

 into the winged butterfly with diiTerent eves, ditTerent antenna*, 

 different mouth parts, different almost everything. And, by 

 the intervention of a curious (piiescent stage called the pupal 



