The Leaf-cutters 



fully transmitted by heredity. Their pieces 

 of leaves vary according to the surrounding 

 vegetation ; they vary in different layers of the 

 same cell. Everything suits them, exotic or 

 native, rare or common, provided that the 

 bit cut out be easy to employ. It is not the 

 general aspect of the shrub, with its fragile 

 or bushy branches. Its large or small, green 

 or grey, dull or glossy leaves, that guides the 

 Insect: such advanced botanical knowledge 

 does not enter into the question at all. In the 

 thicket chosen as a plnklng-establlshment, the 

 Megachile sees but one thing: leaves useful 

 for her work. The Shrike, with his passion 

 for plants with long, woolly sprigs, knows 

 where to find nicely-wadded substitutes when 

 his favourite growth, the cotton-rose, is lack- 

 ing; the Megachile has much wider re- 

 sources: indifferent to the plant itself, she 

 looks only into the foliage. If she finds 

 leaves of the proper size, of a dry texture 

 capable of defying the damp and of a supple- 

 ness favourable to cylindrical curving, that is 

 all she asks; and the rest does not matter. 

 She has therefore an almost unlimited field 

 for her labour. 



These sudden and wholly unprovoked 



269 



