The Hunting Wasps 



level, well-trodden, compact soil, such as that 

 of a path, to prevent the possibility of land- 

 slips and other damage which would ruin her 

 gallery at the first shower of rain. Ours, on 

 the contrary, is not very particular about the 

 nature of her soil, but must have that soil 

 vertical. With this slight architectural modi- 

 fication, she avoids most of the dangers that 

 might threaten her gallery; and consequently 

 she digs her burrows indifferently in a loose 

 and slightly clayey soil and in the soft sand 

 of the Molasse formation, which makes the 

 work of excavation much easier. The only 

 indispensable condition appears to be that the 

 earth should be dry and exposed to the sun's 

 rays for the best part of the day. It is there- 

 fore in the steep road-side banks, in the sides 

 of the ravines hollowed by the rains in the 

 sandstone that our Wasp elects to establish 

 her home. These conditions are common in 

 the neighbourhood of Carpentras, in the part 

 known as the Hollow Road ; and it is here that 

 I have observed Cerceris tuberculata in her 

 largest numbers and that I gathered most of 

 my facts relating to her history. 



The choice of this vertical site is not enough 

 for her: other precautions are taken to guard 

 against the inevitable rains of the season, 

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