How Animals Work. 



the edge of the leaf has a slight curvation, the tiny 

 Caterpillar attaches to it a thread formed by the silk 

 glands in his mouth, and bending his head and the 

 front part of his body as far as he can reach in the 

 opposite direction that is, towards the centre of the 

 leaf fixes the other end of his thread to that spot. 

 Backwards and forwards, from point to point, he swings, 

 weaving a whole series of strands, so that a little cable 

 is at last formed which is attached at one end to the 

 slightly incurved edge of the leaf, and at the other to 

 a spot on the blade of the leaf. The cable is fairly 

 taut, but it has not drawn the edge of the leaf inwards, 

 for the very obvious reason that the little Caterpillar 

 has not sufficient physical force to haul in the cable 

 hand over hand. But now the wee insect changes his 

 position and spinning work, and at once shows him- 

 self a skilled mechanic, for what he cannot accomplish 

 by mere " brute strength " he proceeds to accom- 

 plish by mechanical means. It is obvious that any 

 pressure exerted on the taut cable would shorten its 

 length, and drag the curving edge of the leaf inwards ; 

 and this is precisely what the Caterpillar proceeds to 

 do, not by placing weights on the cable, but in a much 

 stronger and more effective manner, by weaving a 

 series of threads across the cable and at right angles 

 to it, pressing the end of the cable down with the 

 weight of his body as he swings his head backwards 

 and forwards in weaving and fastening down the 

 transverse strands. Having fixed his last cable in this 

 way, the little Caterpillar proceeds to attach another 

 to the margin of the leaf at a short distance from 

 it, repeating the same process again and again, until 



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