The Problem of the Scoliae 



to walk In a fashion the exact contrary of 

 that adopted by other beasts? 



To these questions the science now in 

 fashion always has a reply ready: adapta- 

 tion to environment. The Cetonia-larva 

 lives in crumbling galleries which it bores in 

 the depths of the soil. Like the sweep who 

 obtains a purchase with his back, loins and 

 knees to hoist himself up the narrow passage 

 of a chimney, it gathers itself up, applies the 

 tip of its belly to one wall of its gallery 

 and its sturdy back to another; and the com- 

 bined effort of these two levers results in 

 moving it forward. The legs, which are 

 used very little, indeed hardly at all, waste 

 away and tend to disappear, as does any or- 

 gan which is left unemployed; the back, on 

 the other hand, the principal motive agent, 

 grows stronger, is furrowed with powerful 

 folds and bristles with grappling-hooks or 

 hairs; and gradually, by adaptation to its en- 

 vironment, the creature loses the art of walk- 

 ing, which it does not practise, and replaces 

 it by that of crawling on its back, a form of 

 progress better suited to underground cor- 

 ridors. 



So far so good. But now tell me, if you 

 please, why the larvse of the Oryctes and the 

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