28 



APPLIED ENTOMOLOGY 



story of the metamorphosis differs from that of the Hemimetabola, for 

 after the molt no change in appearance to make the young insect more 

 nearly like the adult takes place. It may be different in some regards 

 besides size, from what it was before the molt, but these differences do not 

 increase its resemblance to what it finally becomes. This holds through- 

 out the feeding period of its existence, so that after three, four or more 

 molts, a caterpillar is still a caterpilar, a grub is still a grub, and this is 

 equally true for all Holometabolous insects. Within the insect during 

 this period, however, changes not perceptible on the surface are taking 

 place, by the construction of portions of the adult which are forming as 



Fig. 32. — Incomplete metamorphosis of a Grasshopper, a, first nymphal instar; 

 b, second instar; c, third instar showing beginning of wings; d, fourth instar; e, fifth instar; 

 /, adult. Figures not drawn to same scale. (Modified from Packard's Text-book 

 of Entomology by perm.ission of the MacMiUan Com,pany, Publishers.) 



buds or ingrowths from various parts of the body, and are termed imagi- 

 nal buds (from "imago," the adult). They are closely compacted and 

 many at least are infolded somewhat like buds, becoming finally ready to 

 open when the proper time comes. And during its feeding instars, the 

 larva, as the young insect in the Holometabola is called, is not only 

 storing energy from its food for its growth at each molt, but also to carry 

 it on through a period yet to be described, during which it must transform 

 into the adult condition while unable to feed and obtain the energy needed 

 for this purpose. 



After a varying number of feeding instars and molts, the young 

 insect or larva has grown sufficiently and has stored within it energy 

 enough to carry it through the remainder of its changes, and internally 

 the essential parts for the adult condition have been formed as far as 



