LEAF-ROLLERS 189 



There is nothing regular, however, about these alterna- 

 tions, which depend upon circumstances known to the 

 animal alone. Perhaps they merely afford a means of 

 resting for a little while without stopping a work that 

 does not allow of interruption. In the same way, our 

 two hands mutually relieve each other by taking it in 

 turns to carry the burden. 



It is impossible to form an exact image of the diffi- 

 culty overcome, without watching, for hours on end, the 

 obstinate straining of the legs, which tremble with ex- 

 haustion and threaten to spoil everything if one of 

 them let go at the wrong moment, or without seeing 

 with what prudence the roller never releases one claw 

 until the five others are firmly fixed. On the one side 

 are three points of support, on the other three points of 

 traction ; and the six are shifted, one by one, little by 

 little, without for a moment allowing their connected 

 mechanical system to flag. A single instant of forgetful- 

 ness or weariness would cause the rebellious piece to 

 unroll its scroll and escape from the manipulator's grasp. 



The work is accomplished, moreover, in an uncomfort- 

 able position. The leaf hangs very much on the slant or 

 even vertically. Its surface is varnished, is smooth as 

 glass. But the worker is shod accordingly. With her 

 tufted soles, she scales the polished perpendicular ; with 

 her twelve meat-hooks, she tackles the slippery floor. 

 Yet this fine set of tools does not rid the operation of all 

 its difficulties. I find it no easy matter to follow the 

 progress of the rolling with the magnifying-glass. The 

 hands of a watch do not move more slowly. The 

 insect stands for a long time, at the same point, with 

 its claws firmly fixed ; it is waiting for the leaf to be 

 mastered and to cease resistance. Here, of course, there 



