38 BEES AND WASPS [OH. 



0. parietum. The little wasp had selected the angle 

 formed between the frame and the ledge of my study 

 window as a suitable spot for her operations. I dis- 

 covered her when she had nearly completed the first 

 of the series of cells. A few more loads of mud were 

 brought to complete the horizontal sides and roof ; 

 then the wasp backed into the cell and, as was after- 

 wards discovered, laid one egg, suspending it by a 

 silken thread to the roof of the cell. Over a dozen 

 small green caterpillars were then in quick succession 

 brought paralysed to the cell and rammed in by 

 vigorous butts from the wasp's head. At length the 

 vertical end wall was added to close the cell and to 

 furnish the back of the second cell of the series. 

 Knowing that in all probability a second cell would 

 be built at once, in the wasp's absence I carefully 

 opened the completed cell and laid the caterpillars 

 and her egg, which was found as already described, 

 beside the ravaged nest on the window-ledge. On 

 her return the insect manifested great consternation 

 at the havoc wrought to her handiwork. However, 

 nothing daunted she hastily gathered the caterpillars 

 together and once again rammed them into the cell, 

 repaired the damages to the walls, and closed the 

 end. But she took no notice whatever of the egg, 

 nor had she, as was ascertained by a later inspection, 

 laid another egg. Her instinct led her right in so far 

 as she realised that the caterpillars should be sealed 



