86 



means the sure deatli of a eertaiii species of insect upon 

 whicli Thalessa pre_vs, known as the Pigeon Tremex 

 (Treniex columba). Adult insects of this hatter famil_y are 

 known as horn-tails because the end of the bod}' terminates 

 in a sharp jjoint or liorn. The larvae are known as wood- 

 borers, many of them doing a great deal of damage to 

 shade trees. 



Tremex is an enemy to oak and elm trees. She has a 

 short but str<uig o\-ipositor with which she bores directly 

 into the wood for a dejith of about an inch, at which depth 

 she deposits her eggs. In about two weeks these eggs 

 hatch and the grubs, or Treniex larvae, commence to bore 

 through the wood; they live upon the wood and its juices, 

 the boring of which when persisted in by numbers of them 

 saps the life of the tree. 



Now Thalessa enters upon the scene ; with her arrival, 

 tlie fate of the Tremex worm is sealed. How she knows 

 just where to bore is a mystery man cannot solve, but she 

 always selects a spot just over the tunnel in which Tremex 

 larva is working. It is then that her wonderful ovipositor 

 comes into plaj' ; this is one of the most marvellous drills 

 in the world, the like of which is beyond the power 

 and skill of man to create. Little larger than an 

 ordinary horsehair, yet it is .1 tube through which 

 Thalessa can la}' her eggs; flexible as a hair, yet it is 

 sturdy enough to penetrate oak. Taking her position on 

 tiptoe, body perj)endicularly elevated relative to the 



