O MELANDER AND BRUES. 



through natural selection and heredity till it manifests itself in the 

 actions just recorded. But the conduct of the male towards his 

 nest-mate, an inhospitable act which a gleam of reasoning intelli- 

 gence would not permit under the circumstances, lends itself 

 rather to the theory of a mechanical instinct, actuated in this 

 case by the chemical nature of Mntilla s poison. If this be so it 

 will be questioned why the bee does not behave as when Mntilla 

 itself approaches. Does the mixture of Mntilla -influence and 



compel an impassive head-on greeting while 



FIG. 4. Combat between Mutilla and Halictus. " Down the hill they roll heed- 

 less of everything but an inborn desire to annihilate each other." 



Mntilla alone induces the male-watcher to turn tail in the manner 

 described on the next page ? 



One little bee once displayed an originality not noticed again. 

 For fully twenty minutes she had waited at the entrance of her 

 home, gently urging admission by advancing to the nest -opening 

 once each minute. The male would retreat a short distance each 

 time but not sufficiently far to admit the female, who would then 

 retire, resting with her antennae almost touching those of the 



