CONTENTS 
CHAPTER PAGE 
I. . . Burrowing Mammalia . . . . . i 
II. . . Burrowing Birds .32 
III. . . Burrowing Reptiles 44 
IV. . . Burrowing Invertebrates .... 47 
V. . . Burrowing Molluscs . . . . .53 
VI. . . Burrowing Spiders ..... 64 
VII. . . Burrowing Insects ( Hymenoptera ) . . 73 
VIII. . . Burrowing Beetles 91 
IX. . . Wood-boring Insects . . . . , .102 
X. . . Pensile Mammalia 117 
XI. . . Pensile Birds . . . . . .121 
XII. . . Pensile Birds —continued . . . .127 
XIII. . . Pensile Birds —continued . . . .137 
XIV. . . Pensile Insects 15 1 
XV. . . Builders .180 
XVI. . . Building Birds . . . . . .184 
a 
