WASPS, SOCIAL AND SOLITARY 



back to the nest she at first passed to one side and went 

 some inches beyond, so that she had to retrace her 

 steps. 



Marchal notes that some wasps are very unskillful 

 in finding their way about, showing by their errors and 

 hesitations not only that they have no sense of direction, 

 but that they are badly served by their memory and by 

 what senses they have. He draws this conclusion from 

 his own observations, one of which had for its subject 

 Pompilus seriaceus, which nests, conveniently for him, 

 in the walls of the rustic summer-house which he uses 

 for a laboratory. A wasp of this species, having caught 

 her spider, had a most wearisome experience in getting it 

 to the nest, which had been previously excavated near 

 the ground. She first carried it straight up, not only 

 passing the opening, but going to the very top of the 

 wall. Realizing that she had gone wrong, she laid it 

 down, and after a prolonged hunt up and down, to 

 the right and to the left, found the nest ; but on leav- 

 ing it again to go for the spider, she started in exactly 

 the wrong direction, down instead of up; and not until 

 forty minutes had been spent in searching alternately 

 for spider and for nest did she finally bring the two 

 together. 



The best evidence that wasps depend upon a know- 



284 



