CONTENTS. 



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I. . . Burrowing Mammalia . . • i 



II. . , Burrowing Birds 32 



III. . . Burrowing Reptiles .... .44 



IV. . . Burrowing Invertebrates .... 47 

 V. . . Burrowing Molluscs S3 



VI. . . Burrowing Spiders 64 



VII. . . Burrowing Insects {Hymenoptera) . . 73 



VIII. . . Burrowing Beetles 91 



IX. . . Wood-boring Insects 102 



X. . . Pensile Mammalia . . . . .117 



XL . . Pensile Birds 121 



XII. . . Pensile Bi^d^— continued . . . .127 



XIII, . . Pensile Birds— continued . . . .137 



XIV. . . Pensile Insects . . . . .151 

 XV. . Builders 180 



XVI. . . Building Birds 184 



a 



