CHAPTER IV 



LARVAL DIMORPHISM 



TF the reader has paid any attention to the 

 •*• story of the Anthrax, he must have per- 

 ceived that my narrative is incomplete. The 

 Fox in the fable saw how the Lion's visitors 

 entered his den, but did not see how they went 

 out. With us, it is the converse : we know the 

 way out of the Mason-bee's fortress, but we 

 do not know the way in. To leave the cell 

 of which he has eaten the owner, the Anthrax 

 becomes a perforating-machine, a living tool 

 from which our own industry might take a 

 hint if it required new drills for boring rocks. 

 When the exit-tunnel is opened, this tool splits 

 like a pod bursting in the sun; and from the 

 stout framework there escapes a dainty Fly, 

 a velvety flake, a soft fluff that astounds us 

 by its contrast with the roughness of the 

 depths whence it ascends. On this point, we 

 know" pretty well what there is to know. 

 There remains the entrance into the cell, a 

 puzzle that has kept me on the alert for a 

 quarter of a century. 



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