7 HE METAMORPHOSIS OF INSECTS 

 6. GRADUAL METAMORPH3-IS 



175 



(Paurometabolous* Development) 



In several orders of insects there exists a type of development that 

 is characterized by the fact that the young resemble the adult in the 

 general form of the body and in manner of life. There is a gradual 

 growth of the body and of the wing rudiments and genital appendages. 



Fig. 194.' Nymph of Mela- 

 no plus, first instar (After 

 Emerton). 



Fig. 195. Nymph of Mela- 

 noplus, second instar 

 (After Emarton). 



Fig. 196. Nymph of Melano- 

 plus, third instar (After Emer- 

 ton) 



Fig. 197. Nymph of Melano- 

 plus, fourth instar (After 

 Emerton). 



Fig. 198. Nymph of Melano- 

 plus, fifth instar (After Emer- 

 ton). 



Fig. 199. Melanoplus, 

 adult. 



But the changes in form take place gradually and are not very great 

 between any two successive instars except that at the last ecdysis 

 there takes place a greater change, especially in the wings, than at 

 any of the preceding ecdyses. This type of metamorphosis is desig- 

 nated as gradual metamorphosis or paurometabolous development. 



The characteristic features oi paurometabolous development are 

 correlated with the fact that the mode of life of the young and of the 



*Paurometabolous: pauros (ira&pos), little; metabole 



, change. 



