214 THE WOOD-WASP 



(Rhyssa persuasoria), one of that cruel race of which 

 many deposit their eggs in the living bodies of other 

 creatures. This animal is provided with a borer or ovi- 

 positor even longer than that of the wood-wasp, with 

 which it drives a shaft into the tunnel of its prey, slips in 

 an egg which hatches speedily into a voracious maggot, 

 and this attacks the grub of Sirex and enters its body, 

 which it devours at leisure. Such, at least, is the grue- 

 some history which the German entomologist Erne had 

 the patience to elucidate ; and most people will be content 

 to take it on trust, for to check minute observations like 

 these demands more time and labour than they can well 

 afford. 



The borer or ovipositor, which plays such an important 

 part in the domestic economy of both Sirex and Rhyssa, 

 is a very remarkable instrument. In both insects the 

 general plan is the same namely, a pair of long sheaths 

 of horny material, enclosing a rigid tube. In the tube of 

 the wood-wasp are enclosed two delicate blades, serrated 

 near the point, which are rapidly vibrated when in 

 action, and pierce the solid wood with a facility which 

 is truly astonishing. Sometimes this borer is driven 

 in so deep that the creature cannot withdraw it, and 

 perishes. 



By a singular coincidence, on the very same day on 

 which I captured the wood-wasp in my own garden the 

 first that I had ever had an opportunity of examining in 

 Scotland I drove over to a place some fifteen miles 

 distant. A young lady of the house, who took me to see 

 her flower-borders, paused as we passed under a rustic 

 arch made of rough larch poles, and showed me the dead 

 body of a female Sirex, the duplicate of the one I had 



