4O FIELD ZOOLOGY. 



removed from the parent form. In the case of the 

 ametamorphic insects, we may speak of the young as 

 undergoing some such maturing as do the young of some- 

 what higher animals, development without metamorpho- 

 sis ; while the incomplete metamorphosis sorts represent a 

 type between ametamorphic and complete metamorphic. 



Incomplete Metamorphosis. 



As an example of incomplete metamorphosis, we 

 may take the box elder bug that is becoming such a pest 

 wherever box elder trees are grown. Probably these 

 trees have much to do with the appearance of the bug. 

 All animals, even in the human tribe, follow their food 

 around the world; or else, if 'they have the power of 

 initiative, as human beings do, they take their foods along 

 to the new place of abode. From the egg there hatches 

 a tiny red bug, soft-bodied, and without wings, yet 

 enough like its parents to have the same mouth parts and 

 the same feeding habits. These small bugs feed, so far 

 as we know, on the sap of the young, tender stems and 

 twigs. They seem not to be confined to box elder trees, 

 though probably feeding there more often than elsewhere. 

 To accommodate the increasing bulk, the bug sheds its 

 old skin frequently. The body wall becomes hardened 

 by chitin, and will not yield as the insect continually 

 grows; hence it is split open and the insect casts it off; 

 but before this happens the insect has made itself a new 

 skin inside the old one, and when it emerges, the new 

 wet, wrinkled skin stretches and so makes room for the 

 insect grown larger. The wings are represented, at first, 

 by bud cells under the skin, but gradually these grow 

 until the rudiments of wings appear beyond the body 

 wall in the shape of wing pads. The body continues to 



