THE CHARACTERS AXD METAMORPHOSES OF IX SECTS. 



within which the transformations are undergone. This case is 



termed a cocoon. Frequently these 



cocoons are made within a rolled 



leaf (Fig. f), or on the surface of 



the ground, where they are covered 



with dry grass or other rubbish. 



Certain hairy caterpillars make 



their cocoons largely of their hair. 



which they fasten together by a 



, . -. r ... Fig. 7. — Cocoon of Telia. 



thin film ot silk. 



Immature Forms of Insects with Incomplete Metamorphosis, The 

 Nymph. — The terms larva and pupa are applicable only to the early 



Fig. 8.— Nymph of Melanoplus, first stage. 

 (After Emerton.) 



Fig. 9. — Nymph of Melanoflus, second stage. 

 (After Emerton.) 



stages of insects with a complete metamorphosis. In the case of 

 those in which the transformation is an incomplete one, the changes 

 through which the immature insect passes after leaving the egg are 



*?=*» 



Fig. 10. — Nymph of MelanofiZus, third stage. 

 (After Emerton.) 



Fig. 11. — Nymph of Melanoplus, fourth stage. 

 (After Emerton.) 



so gradual that one cannot indicate any point at which the insect 

 ceases to be a larva and becomes a pupa. Recent writers have used, 

 therefore, the term nymph (a term formerly used as a synonym of 

 pupa) to designate the immature forms of insects with an incomplete 

 metamorphosis. This term is applied to all the stages between the 

 egg and the fully winged or adult state. 



A nymph when it leaves the egg has no indications of wings. 

 After undergoing a greater or less number of moults, differing in 

 different species, small prolongations appear projecting from the 



