16 LIST OF ILLUSTRATIONS 



FACING PAGE 



A tiny solitary bee resting between journeys 161 



Making a plaster cast of the bee's burrow 161 



Entrance to the bee's tunnel showing surroundings 161 



Model of the bee's nest made from a plaster cast 163 



Interior of the bee's burrow showing cell and food 163 



Excavating the cast of the burrow 163 



Caterpillar of a geometrid moth which resembles a twig . . . following 164 



Caterpillar which mimics the excretia of a bird following 164 



Chrysalis of the mourning cloak butterfly 168 



Cochlidiid caterpillar which mimics a leaf-bud . . 168 



Thread-legged bug in its original environment following 170 



Poison spines of the lo caterpillar following 170 



Wood lice or pill bugs . 173 



A thysanuran or bristle-tail 173 



