118 ETON NATUEE-STUDY 



DIRECTIONS TO THE PUPIL 



(2) Make headings as usual, and fill in details as to the colour, 

 shape, and size of the gall, which you see growing from the oak 

 twig. Sketch it, and leave a space for a finished drawing. 



(3) Examine the specimen further. Has it a skin ? Of what 

 sort of substance is it within ? 



FIGURE 227. A Marble Gall showing the 

 holes through which the insect in- 

 habitants have escaped. 



FIGURE 228. A Marble Gall cut through 

 showing the cavities occupied by the 

 grub. 



(4) Split the gall through the middle and draw what you see. 

 Discover, if possible, the grub (that hatched from the egg by laying 

 which the parent insect caused the oak to produce the gall, in the 

 first place). 



(5) Describe the grub and others that may have sprung from 

 the eggs of different insects which take advantage of the food and 

 shelter afforded by the gall. 



