70 THE SOLITARY WASPS. 



parasitic flies. Can it be that there is one spot in the world 

 where the wasp is free from them? 



Probably Monedula, like Bembex, lives in colonies, since it 

 is said that as a usual thing many of their holes are found close 

 together. It occasionally captures insects on the wing but 

 more frequently pounces down on them when they are at rest. 



This species, then, differs from Bembex spinolae in its cap- 

 ture of other insects, besides flies, and in its habits of laying the 

 egg in the empty nest, no food being brought until the grub 

 is hatched. In both respects the southern species seems to have 

 made an advance upon the intelligence of our Bembecidae. 



Another interesting variation is that of Bembex ciliata ob- 

 served by Mr. Bates in Santarem.* This wasp excavates her 

 gallery and then goes off to catch her fly, leaving the door open. 

 This sometimes happens with spinolae, but never with the 

 European species rostrata, and, as we have seen, Monedula also 

 carefully closes the door before leaving it. Ciliata,to be sure, 

 does all that is necessary, since after the fly has been taken in 

 and the egg laid, the doorway is filled up. Ciliata, as well as 

 spinolae, circles about and takes her bearings carefully before 

 leaving the spot. 



Mr. Bates has also some notes on Monedula signata, which 

 differs to a remarkable degree from punctata since it not only 

 taken nothing but flies, but even confines itself to a single 

 species, although it must sometimes go half a mile away to find 

 it. This reminds us of Pompilus quinquenotatus which never 

 takes anything but Epeira strix. 



A considerable contribution to our knowledge of the genus 

 Bembex has been made in the paper by Wesenberg (written in 

 Danish) which has already been referred to. This paper deals 

 with Bembex rostrata. It was translated for Mr. Ashmead by 

 Mr. Martin Linell.f The account is most interesting. 



It seems that 1 rostrata makes its nest in solid sand, covering 



*Naturalist on the Amazon, p. 181. 



fAculeate Hymenoptera, III., Psyche, vol. 7, no. 216, p. 62. 



