THE LIFE OF A SOLITARY WASP 215 

 wasp has a wonderful knowledge of the anatomy of 

 caterpillars ! " It is," writes Fabre, " in this triple blow 

 that the infallibility, the infused science, of instinct, 

 appear in all their magnificence." 



These words are in the main true, but more recent 

 investigations have shown that instinct is, in this case, 

 not absolutely infallible. The wasp does sometimes 

 make a " boss shot." It occasionally happens that a 

 stab fails to reach the nerve ganglion. When the wasp 

 has stored the cell with eight caterpillars she closes 

 it by roofing it with mud. I believe that eight is the 

 number of caterpillars she allows to each egg, but there 

 again I speak not with certainty. 



These observations were made at random and were 

 often interrupted. After the cell had been closed there 

 was still plenty of room left in the hole in the bed- 

 post ; in this space the wasp laid another egg, killed 

 more caterpillars, and then closed the cell with mud, 

 making the top of the roof flush with the summit of 

 the post. She then proceeded to stock the hole in the 

 bed-post, behaving in precisely the same way as before. 

 Having completed the second nest, she forthwith began 

 to line the third hole with mud, and was stocking it 

 with caterpillars, when I cut short her life. I had to 

 sacrifice her in the interests of science, in order to find 

 out the species to which she belonged. 



Five days after she had closed the first nest I opened 

 it, and found that all the caterpillars had disappeared, 

 and that a great fat white grub, fully an inch in length, 

 had taken their place. This had emerged from the 

 egg, and then devoured all the caterpillars. The length 



