Author's Preface 



are kept in place by hooks or bolts. The 

 top one opens for food to be distributed and 

 for the cleaning of the cage; it is the kitchen- 

 door for everyday use. It is also the en- 

 trance-gate for any new captives whom I 

 succeed in bagging. The bottom shutter, 

 which keeps the layer of earth in position, 

 is opened only on great occasions, when we 

 want to surprise the insect in its home life 

 and to ascertain the condition of the progress 

 underground. Then the bolts are drawn; 

 the board, which is on hinges, falls; and 

 a vertical section of the soil is laid bare, 

 giving us an excellent opportunity of studying 

 the Dung-beetles' work. Our examination 

 is made with the point of a knife and has to 

 be conducted with the utmost care. In this 

 Avay we get with precision and without diffi- 

 culty industrial details which could not always 

 be obtained by laborious digging in the open 

 fields. 



Nevertheless, out-door investigations are 

 indispensable and often yield far more 

 important results than anything derived from 

 home rearing; for, though some Dung- 

 beetles are indifferent to captivity and work 

 in the cage with their customary vigour, 

 others, who are of a more nervous tempera- 

 ment or perhaps more cautious, distrust my 



xviii 



