98 THE CANADIAN ENTOMOLOGIST. 



to be not easily seen. In the Uroceridce this complex instrument, modi- 

 fied to form a borer, is much larger, projecting generally beyond the body 

 and easily examined. There are still the hollowed pieces which when 

 closed form the scabbard, but the parts which were seen acting as backs, 

 to steady the saws, are now joined or welded together into a cylinder, 

 within which are placed two spiculse or needles corresponding to the 

 original saws. These needles, as fine as bristles, are worked by inde- 

 pendent muscles, and can thus be protruded a little beyond the end of the 

 borer, acting like small drills. In the true ichneumons this apparatus is 

 still further modified, and in some species attains a great length. If the 

 piercer of a Horn-tail be extracted from its scabbard and the tip felt with 

 the finger, .it will be found appreciably roughened, and even the naked 

 eye shows it to be ridged. Under the glass it has much the appearance 

 of a diminutive augur. The tapering end is notched at close intervals, 

 while on each side the dividing line which runs along the under side of 

 the cylinder are short ridges placed diagonally to the line and forming 

 triangles, with the apex toward the end of the instrument. Early investi- 

 gators, as has been shown, were unacquainted "with the larvae of the 

 Uroceridcz and concluded them to be insectivorous, and as late as the time 

 of Westwood this view still had adherents. Reliable observations have 

 long since proved them to be wood-eaters, and have established the fact 

 that the borer of the female fly is used not for depositing eggs in other 

 insects, but for drilling holes in wood in which to place them. It is not 

 only in soft wood that these holes are bored, for I have seen the insects at 

 work on such tough trees as elm, oak and beech, both living and dead. 

 The fly stands up upon its long legs so that its body is kept well out from 

 the wood ; the borer is then bent down so as to be at right angles to the 

 body of the insect, and perpendicular to the surface to be pierced. The 

 end is then inserted by pressure accompanied by a movement of the body 

 from side to side, and by such awl-like motions the holes are pierced 

 sometimes to the depth of half an inch or more. Often the insect is 

 unable to withdraw the augur, so firmly has it been worked in, and I have 

 found many dead ones which had thus perished in the discharge of their 

 duty, that of continuing their species. The grubs hatched from the eggs 

 thus laboriously deposited are fleshy and cylindrical, with rounded, horny 

 heads and very strong jaws capable of cutting deeply into the trees 

 infested by them. Indeed, apparently well authenticated instances are 

 recorded of their having perforated lead to some depth, a feat which 



