230 



THE FLOKAL WOELD AND GARDEN GUIDE. 



tomologista to be formed for the purpose of affording the female an 

 opportunity to turn round in the tunnel, and beat a retreat should 

 she survive the work in which she is engaged. Bat they can hardly 

 be for that purpose, and after a close examination of various pieces 

 of wood tunnelled in the manner here shown, it is difficult to sup- 

 pose that they are provided for any other purpose than as recepta- 

 cles for the eggs. When the eggs are hatched, the larvre proceed to 

 the right and left of the tunnel, eating their way as they go, and these 

 lateral channels widen as the larvae iocrease in size, and finally ter- 

 minate in a rather wide and blunt cavity. 



In this cavity the larva sinks into a dormant state, and under- 

 goes its change to the winged state. The beetle when fully developed 

 bores its way through the bark and emerges into the open. Its open air 

 existence is exceedingly brief, for the female sooa begins to bore her 

 way iuto the bark to deposit her eggs as in the previous generation. 

 The main tunnel formed by the lemale is always in an upward 

 direction, and it is usually from two to three and a half inches in 







■■*■*" Ifci 



Fig. 3. — Elm-wood, showing tracks of B. chalcographuB and B. typographuB. 



length. The larv» feed upon the tree throughout the summer, 

 autumn, and winter, and as tLiey may in the case of large trees amount 

 to many thousands, it is not difficult to conceive the immense 

 amount of injury an army of this beetle is capable of effecting. 



The larvae of various species of Bostrichus make branching chan- 

 nels very similar to those formed by Scolytus dexfruetor, a3 a reference 

 to Fig. 3 will show ; the lines or channels at a, in this figure, are those 

 of JB. cliahographiis, and those marked B, are formed by B. topo- 

 graphus. The last-mentioned species is rather the largest insect of 

 the two ; but both are about equal in the injury they do to the trees. 



The larvae of the Stag Beetle and of the Goat Moth also bore 

 their way into the elm as well as into other trees ; but, fortunately, 

 neither are sufficiently plentiful to do very much mischief. Were 

 they plentiful they would be more direful in their effects upon the 

 trees than either of the other enemies, for they make holes of large 

 size, and bore their way to quite the heart of the tree ; so that if a 



