Page:The Life of the Spider.djvu/25

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 cutting into fine ellipses the delicate material of the robinia? What ideal pattern guides her scissors? What measure dictates the dimensions? 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 mechanism, the mere outcome of her organization, 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