Preface 



but for a moment and in regard to a single 

 detail : 



'With the oval pieces, the question changes. 

 What model has the Megachile when cut- 

 ting into fine ellipses the delicate material of 

 the robinia? What ideal pattern guides her 

 scissors? What measure dictates the dimen- 

 sions ? One would like to think of the insect 

 as a living compass, capable of tracing an 

 elliptic curve by a certain natural inflexion 

 of the body, even as our arm traces a circle 

 by swinging from the shoulder. A blind mech- 

 anism, the mere outcome of her organiza- 

 tion, would in that case be responsible for her 

 geometry. This explanation would tempt 

 me, if the oval pieces of large dimensions 

 were not accompanied by much smaller, but 

 likewise oval pieces, to fill the empty spaces. 

 A compass which changes its radius of itself 

 and alters the degree of curvature according 

 to the exigencies of a plan appears to me an 

 instrument somewhat difficult to believe in. 

 There must be something better than that. 

 The circular pieces of the lid suggest it to us. 



'If, by the mere flexion Inherent in her 

 structure, the leaf-cutter succeeds in cutting 



21 



