ADAPTATIONS 



307 



piercing ovipositors, by means of which the eggs are de- 

 posited in the ground or in the leaves or stems of green 

 plants, or even in the hard wood of tree-trunks. Some of 



the scale insects se- 

 crete wax from their 

 bodies and form a 

 large, often beautiful 

 egg-case, attached to 

 and nearly covering the body in 

 which eggs are deposited (Fig, 

 179). The various gall insects 

 lay their eggs in the soft tissue 

 of plants, and on the hatching of 

 the larvae an abnormal growth, 

 of the plant occurs about the 

 young insect, forming an in- 

 closing gall that serves not only 



but to furnish it with an abun- 

 dance of plant-sap, its food. The 



to her body. (The lines at the left young insect remains in the gall 



tLTns h ec fi tsr indiCatethe8iZe f ^^ ii; completes its develop- 

 ment and growth, when it 



gnaws its way out. Such insect galls are especially abun- 

 dant on oak trees (Fig. 180). The care of the eggs and the 

 young of the social insects, as the bees and ants, are de- 

 scribed in Chapter XXII. 



