20 THK HUMANIZING OF THB BRUTE. 



their nature, though sometimes for the sake of a high- 

 er end they may fall short of their immediate purpose. 



A classical example admirably adapted to illustrate 

 the point at issue is the life-history of the famous 

 leaf-roller Rhynchites betulse L. ; for in constructing 

 the cradle for its young this tiny black snout-beetle 

 has for ages been carrying out a problem which, at 

 least in its entirety, was not known to man before the 

 year 1673, when the great mathematical genius, Huy- 

 gens, published his celebrated "Horologium Oscilla- 

 torium. ' ' 



L,et us give a brief account of the famous beetle 

 and its problem, basing our remarks on the investiga- 

 tions and writings of Debay l ) and of Wasmann a ) 

 and upon observations made by ourselves many years 

 ago in Holland. 



In early spring, as soon as the Rh, betula 3 ) has 

 emerged from the ground, it climbs up a birch-tree, 

 where, after mating, the female at once proceeds to con- 

 struct from the pliant young birch leaves a little house 

 for her offspring. Carefully examining the edge of a 

 leaf, the beetle suddenly stops and begins to cut the out- 

 lines of what is to be the cradle for its little ones. It 

 starts at the upper margin of one side of the leaf. 

 Directing its head toward the upper part of the central 

 rib, it cuts with its admirably adapted mandibles an 

 S-shaped curve, whose terminal touches the leaf's 



1 ) Dr. Debay, Beitraege zur Entwicklungsgeschichte der 

 Ruesselkaefer aus der Familie der Attelabiden, Bonn, 1846. 



J ) Erich Wasmann, S. J., Der Trichterwickler, Muenster, 

 1884. The following account was first published in the 

 Scientific American, April, 1901. 



3 ) From betula, birch-tree. 



