CRABRO 



not only flies, but long- bodied gnats, and all of them 

 seemed to have been brought home uninjured. When 

 the freshest cell was opened some flew away, others 

 were walking about, and all were lively. The wasp egg 

 was laid on the under side of the neck ; and although 

 we could not be certain of the exact time of laying we 

 thought it hatched at the end of thirty-six hours. From 

 ten to sixteen flies were provided for each larva. 



A month later we found Crabro lentus nesting in the 

 ground. Her tunnel ran down obliquely for six and one 

 half centimeters, and had an enlargement at the end. 

 Two bugs and a fly were in the nest, when we opened it 

 before the provision was completed. To find sexmacu- 

 latus taking both flies and gnats was surprising, so rigid 

 are the family traditions of the wasps; still, she might 

 feel that so long as she drew the line at Diptera she was 

 all right. But to believe that one wasp, a Crabro, too, 

 with all the marks of conservatism about her, would 

 take such diverse things as bugs and flies, is almost too 

 much to believe. It is true that Crabro wesmaeli is said 

 to use both flies and bugs; 1 but some accident may 

 have led to this supposition, and stronger evidence is 

 needed to prove that there is variability in so deeply 

 seated an instinct. 



1 Sharp, Insects, page 130. 

 101 



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