Ch. Till. SPIDERS THE PREY OF WASPS. 133 



of 1857 in North Wales, where the foxglove was very 

 abundant, and watched the flowers throughout the 

 season, but only once saw a small bee reach the nectary, 

 though many were seen trying in vain to do so. 



Great attention has of late years been paid by natu- 

 ralists to the wonderful contrivances amongst flowers to 

 secure cross fertilisation ; but the structure of many 

 cannot, I believe, be understood, unless we take into 

 consideration not only the beautiful adaptations for 

 securing the services of the proper insect or bird, but also 

 the contrivances for preventing insects that would not be 

 useful from obtaining access to the nectar. Thus the 

 immense length of the Angrcecum sesquipedale of Mada- 

 gascar might, perhaps, have been more easily explained 

 by Mr. Wallace, if this important purpose had been 

 taken into account. 



The tramway in some parts was on raised ground, in 

 others excavated in the bank side. In the cuttings the 

 nearly perpendicular clay slopes were frequented by 

 many kinds of wasps that excavated round holes of the 

 diameter of their own bodies, and stored them with sting- 

 paralysed spiders, grasshoppers, or horse-flies. Amongst 

 these they lay their eggs, and the white grubs that issue 

 therefrom feed on the poor prisoners, I one day saw a 

 small black and yellow banded wasp (Pompihis poUstoides) 

 hunting for spiders ; it approached a web where a spider 

 was stationed in the centre, made a dart towards it ap- 

 parently a feint to frighten the spider clear of its web ; at 

 any rate it had that effect, for it fell to the ground, and 

 was immediately seized by the wasp, who stung it, then 

 ran quickly backwards, dragging the spider after it, up a 



