92 THE LIFE AND LOVE OF THE INSECT 



one place, moderate in another, has succeeded in harden- 

 ing it into a permanent horn. 



Could the future not complete a work the design of 

 which is so very clearly traced ? We ask ourselves this 

 the more readily inasmuch as every appearance encour- 

 ages the question. Examine under the magnifying- 

 glass the frontal horns of Onthophagus Taurus in the 

 pupa state ; then consider as carefully the spear upon 

 the corselet. At first, there is no difference between them, 

 except the general configuration. In both cases, we find 

 the same glassy aspect, the same sheath swollen with a 

 crystalline moisture, the same incipient organ plainly 

 marked. A leg in formation is not more clearly declared 

 than the horn on the corselet or those on the forehead. 



Can time be lackmg for the thoracic growth to organize 

 itself into a stiff and lastmg appendage ? The evolution 

 of the nymph is swift ; the insect is perfect in a few weeks. 

 Could it not be that, though this brief space suffice to 

 promote the maturity of the horns on the forehead, the 

 thoracic horn requires a longer time to ripen ? Let us 

 prolong the nymphal period artificially and give the germ 

 time to develop itself. It seems to me that a decrease 

 of temperature, moderated and maintained for some 

 weeks, for months if necessarj^ should be capable of 

 bringing about this result, by delajong the progress of the 

 evolution. Then, with a gentle slowness, favourable to 

 delicate formations, the promised organ wiU crystallize, 

 so to speak, and become the spear heralded by appear- 

 ances. 



The experiment attracted me. I was unable to under- 

 take it for lack of the means whereby to produce a cold, 

 even and lasting temperature. What should I have 

 obtained if my penury had not made me abandon the 



