202 THE SOLITARY WASPS. 



Marchal does not agree Avitli Tabre in his belief that wasps 

 are endowed not only with tools but with the method of using 

 them, the gift being original, perfect from the beginning, not 

 modified by past or future. The action of Cerceris does not 

 imply any mysterious science. She runs the end of her abdo- 

 men along the imder surface of the thorax of the bee and stings 

 at the division of the segments — that is at the points where the 

 sting can enter. The order in which the strokes are given is 

 very variable, and if the neck is protected by gum-arabic, so 

 that it is impervious, the stings between the pro- and mesothorax 

 give just the same result. All that is necessary is that the 

 sting shall reach the line of nervous matter that runs along the 

 ventral face of the thorax. As a matter of fact it does not 

 touch the ganglia, but enters just half way between them. The 

 distance is small and the poison quickly reaches the nervous 

 centers. (PI. X. fig. 4.) 



The order in which the stings are given is variable. We 

 may consider that there are four classes: 



In class A. the sting is given: 



1st, at the neck. 



2nd, at the articulation of the prothorax and the mesothorax. 



3rd, at the neck. 



In class B. it is given: 



1st, at the neck. 



2nd, at the articulation of the prothorax and the mesothorax. 



In class C. it is given: 



1st, at the neck. 



2nd, at the articulation of the prothorax and the mesothorax. 



3rd, behind, toward the origin of the abdomen. 



In class D. it is very probably given in a considerable num- 

 ber of cases, either only in the articulation of the prothorax and 

 the mesothorax, or only in the neck. 



Cerceris is far from using the exquisite method of malaxa- 

 tion followed by Sphex, as described by Fabre. She is on the 

 contrary, quite brutal. She pricks and squeezes the neck of the 



