^94 INSECT LIFE xxi 



faculties, in order to accomplish the final act of its 

 metamorphosis, i.e. issuing from the cocoon or cell. 

 Its mandibles furnish it with scissors, file, pick, and 

 lever to cut, gnaw, and pull down not only its 

 cocoon and wall of mortar, but any other barrier 

 not too tenacious which may be substituted for the 

 natural wall of its nest. Moreover, — and this is a 

 chief condition, without which its outfit would be 

 useless, — there is, I will not say the will to use these 

 tools, but an inward stimulus inviting it to 

 employ them. The hour to come forth having 

 arrived, this stimulus awakens, and the insect sets to 

 work to bore a passage. 



In that case it matters little whether the material 

 to be pierced is natural mortar. Sorghum pith, or 

 paper. The imprisoning cover will not resist long 

 It even matters little if the obstacle be thickened 

 and a paper barrier be added to the earthen one. 

 Both co'int as one if there be no interval between 

 them, and the insect passes through them because 

 this coming forth seems to it a single action. With 

 the paper cone, whose wall is at a short distance, 

 the conditions are changed, although the total thick- 

 ness of barrier is really the same. The insect has 

 done all that it was destined to do in order to free 

 itself. To move freely on the mortar dome means 

 to it that deliverance is achieved. It has bored its 

 way out ; the work is accomplished. But round 

 the nest another barrier presents itself — the paper 

 wall. To pierce through, the action already accom- 

 plished must be repeated — that action which the 

 insect has to perform but once in its life. It must 

 double that which naturally is but single ; and it 



