Chap. I. INSTINCT OF LOCALITY. 33 



neath their bodies issues in continuous streams. They 

 are solitary wasps, each female working on her own 

 account. After making a gallery two or three inches 

 in length in a slanting direction from the surface, the 

 owner backs out and takes a few turns round the orifice 

 a}3parently to see whether it is well made, but in 

 reality, I believe, to take note of the locality, that she 

 may find it again. This done, the busy workwoman flies 

 away ; but returns, after an absence varying in different 

 cases from a few minutes to an hour or more, with a 

 fly in her grasp, with which she re-enters her mine. 

 On again emerging, the entrance is carefully closed with 

 sand. During this interval she has laid an egg on the 

 body of the fly which she had previously benumbed 

 with her sting, and which is to serve as food for the 

 soft, footless grub soon to be hatched from the egg. 

 From what I could make out, the Bembex makes a 

 fresh excavation for every egg to be deposited ; at least 

 in two or three of the galleries which I opened there 

 was only one fly enclosed. 



I have said that the Bembex on leaving her mine 

 took note of the locality : this seemed to be the expla- 

 nation of the short delay previous to her taking flight ; 

 on rising in the air also the insects generally flew round 

 over the place before making straight off. Another 

 nearly allied but much larger species, the Monedula 

 signata, whose habits I observed on the banks of the 

 Upper Amazons, sometimes excavates its mine solitarily 

 on sand-banks recently laid bare in the middle of the 

 river, and closes the orifice before going in search of 

 prey. In these cases the insect has to make a journey 



VOL. II. d 



