26 Insect Architecture. 



ing its singular burrows. The sort of sand-bank which it 

 selects is hard and compact ; and though this may be more 

 difficult to penetrate, the walls are not liable to fall down 

 upon the little miner. In such a bank, the mason-wasp 

 bores a tubular gallery two or three inches deep. The sand 

 upon which .Reaumur found some of these wasps at work was 

 almost as hard as stone, and yielded with difficulty to his 

 nail ; but the wasps dug into it with ease, having recourse, as 

 he ascertained, to the ingenious device of moistening it by 

 letting fall two or three drops of fluid from their mouth, 

 which rendered the mass ductile, and the separation of the 

 grains easy to the double pickaxe of the little pioneers. 



When this wasp has detached a few grains of the moistened 

 sand, it kneads them together into a pellet about the size of 



Nests, &c., of Mason- Wasps. About half the natural size. 



a, The tower of the nest ; b, the entrance after the tower is removed ; c, the cell; d, the 

 cell, with a roll of caterpillars prepared for the larva. 



one of the seeds of a gooseberry. With the first pellet which 

 it detaches, it lays the foundation of a round tower, as an 

 outwork, immediately over the mouth of its nest. Every 

 pellet which it afterwards carries off from the interior is 

 added to the wall of this outer round tower, which advances 

 in height as the hole in the sand increases in depth. Every 

 two or three minutes, however, during these operations, it 



