The Bull Onthophagus: the Nymph 



metamorphosis Is not deep down; variations 

 of temperature are easily felt. On the other 

 hand, the seasons are capricious, especially 

 the spring. Under the skies of Provence, 

 the months of May and June, if the mistral 

 lend a hand, have periods when the ther- 

 mometer drops in such a way as to suggest 

 a return of winter. 



To these vicissitudes add the influence of 

 a more northerly climate. The Onthophagi 

 occupy a wide zone of latitude. Those of 

 the north, less favoured by the sun than those 

 of the south, might quite possibly have the 

 date of their transformation postponed by a 

 change in the weather and consequently be 

 subjected to a lower temperature for several 

 weeks. This would spin out the work of 

 evolution and give the thoracic armour time 

 to harden into horn, at rare intervals, as 

 chance may prescribe. Here and there, 

 then, the requisite condition of a moderate 

 or even low temperature at the time of the 

 nymphosis actually exists, without the need 

 of any artificial agency. 



Well, what becomes of this surplus time 

 placed at the service of the organic labour? 

 Does the promised horn ripen? Not a bit 

 of It: It withers just as It does under the 

 stimulus of a hot sun. In the records of 



417 



