NrATEKXAL INSTINCTS : MOTHERHOOD. 205 



obviously impracticable to descend to the ground and secure mud, vege- 

 table mould, and cliippage, as is the custom with those species wliose 

 cocoons are fixed ujron various surfaces, and whose makers can conveni- 

 ently resort to terra firma. In the case of our little Caudata, whose net 

 swings in the open air, tlie ehippage of slaughtered insects is after all 

 the most convenient material at hand. Necessity here, as among human 

 creatures, appears to have been the motlier of invention, aided much by 

 oiiportunity. The hard, dry shells are cut up into pieces, which are stuck 

 to every part of the egg sac until the whole is covered, often very closely. 

 Thus, in a single cocoon one will be able to detect the wings, head, elytra, 

 abdomens, and other parts of various orders of insects, many of them 

 having bright colors. 



In these various methods of exercising this general habit one can 

 find no motive which meets the facts of the case as well as that of ma- 

 ternal solicitude. Mother love has found expression in the armoring of 

 the silken vessel within which the eggs are enclosed, thus protecting 

 them from the enemies which are to beset them. The motive is none 

 the less potent, and none the less to be recognized, because of the fact 

 that the mother herself could have had no knowledge of the character 

 of those enemies to wliich her jirogeny would be exposed, and acted in 

 obedience to an imi)ulse within which we can trace no factor of personal 

 reasoning. 



