MARCH AL ON CERCERIS ORNATA. 201 



supply of bees lie may continue to assist, as long as he wishes, at 

 the manoeuvre of Cerceris. It is not even necessary to take the 

 wasp with her victim; it is enough to shut in together an Halyc- 

 tus and a female Cerceris, always with the condition that the 

 latter has been captured while hunting. "Five successive 

 times," says Marchal, "I saw Cerceris return to the assault and 

 recommence the same manoeuvre on the unhappy bee. To 

 speak truly the immediate result obtained by this succession of 

 operations did not appear to me to correspond with the energy 

 employed, and after the fifth operation the immovability was 

 scarcely greater than after the first. Moreover the one which 

 received the assault five times, taken at two o'clock, still moved 

 its legs the next morning after the abdomen was excited; this 

 is precisely what resulted from a single operation." 



The instinctive act of Cerceris, then, may be considered a 

 reflex due to the sight of the bee and able to be accomplished 

 an indefinite number of times so long as the wasp is in chase. 



At the moment of capture Cerceris seizes the bee brusquely,, 

 clasping the anterior part of the body with her mandibles. Her 

 recurved abdomen darts the sting into the neck at the articula- 

 tion of the head and thorax, the stroke being given vigorously 

 as though it were of capital importance. For a few moments 

 the two combatants roll on the ground; one or two quick strokes 

 are given under the thorax, principally between the prothorax 

 and the mesothorax, and the bee becomes motionless; then 

 Cerceris holds her victim face to face with her, looks at it a few 

 seconds, and turns it around so as to bring the neck opposite her 

 mandibles. The bee being thus adjusted the wasp proceeds to 

 dig at the nape of the neck, squeezing it for from two to four 

 minutes. This process is usually performed within the nest, 

 and it is noticeable that Cerceris, after the malaxation, does not 

 drag her bee by an antenna as she would do if the operation 

 usually preceded the entrance into her hole. On the other 

 hand the wasp sometimes gives the strokes with her sting and 

 then, not proceeding to malaxation, at once begins to drag the 

 bee as if seeking to regain the nest. 



