GUESTS AND PARASITES OF HALICTUS. 5 



Other. The Mutilla, too. is armed with a powerful sting, half the 

 length of her abdomen, but the sagacious Halichis grasps her 

 enemy about the waist and most successfully evades the sharp 

 thrusts. These combats continue for many minutes, concluded 

 either by the invulnerable Miitilla slipping from the bee's grasp, 

 for her body is hard and sleek, or by the death of the more 

 plucky Halichis. Each colony, where everA-thing seemingly is 

 peace and content, is thus turned into a field of carnage, with the 

 bodies of one or more females ruthlessly tumbled to the bottom 

 of the hill. If the bee escapes unscathed, ^vhich happily is the 

 more usual outcome of these struggles, she spends a few moments 

 in preening her body, and then returns to her nest. But no 



r . . ;. Nes: of //.;.';.. -.v.. ai Woods Holl, M.ifi. 



greeting awaits her after her loyal struggle. \\"hen she hurriedly 

 left the nest the male waiting his turn in the tunnel below quickly 

 took her place as guard at the door, and now he blocks the 

 entrance as obstinatelv as tliough it were a stranger becrcnncr 

 admittance. The taint of Mutilla is still to be recognized on the 

 body of the female and probably overpowers her family smell. 

 For quite a minute she must remain at the door parleying with 

 her mate before he is convinced of her identity. 



This obser\-ation is of interest when considering the organic 

 dependence of instinct. Fear of Mutilla has been cultivated 



