30 



transverse yellow bands across the long cylindrical abdomen. The 

 body is about an inch and-a-half or two inches long, and the dark 

 wings spread about two inches and-a-half. Concealed as in a 

 sheath in the projection from the end of the abdomen is the borer, 

 a black, needle-like rod. By means of this the insect drills holes 

 into the wood of the elm, and in the holes thus formed the eggs 

 are laid. Besides the elm, other trees are visited. 



Figure 20. 



Larva of Tremex Coi.UMBA. 



Figure 21. 



Rhyssa lunator. 



The eggs hatch into a cream colored grub which bores into the 

 wood. 



Rhyssa a train and R/iyssa luuator^ hgure "21, are parasites of 

 the Tremex. By its long ovipositors this insect penetrates the 

 trees infested by Tremex, and places its eggs in or near the 

 burrows, and the larvai hatching from these destroy the Tremex 

 larvae. The male Tremex diflbrs from the female, in the absence 

 of the borer, and its shorter body ; he also lacks the yellow mark- 

 ings, being reddish brown and black. He is also very much 

 smaller, the expanse of wings being not over two inches, except 



