EXEMii-:s OF i:\i:r(;ki:1':x or coxiferouS trees 



\M»Ki\ (>i iiAi:i\ itoici i;> IN riM 



It is ilithcult tor th(' avcraot- rc-adcr lo i^ain a just conception of llic 

 injurious ciiaracti-r ot tlu'Sf insects hy a perusal of a nuinher of detached 

 notices ot the work ot associated species. It is therefore ])roposed to _S4"i\e 

 at the outset a Ijrief resume of the conditions we ha\e found in tiie Ikulson 

 valley. The white pines in this section have suffered seriously durint,'' the 

 last three or four \ears and a consiilerahle |)roportion of the damage is 

 diu; t(j tin- work (_)f hark borers and their associates. The extremely 

 injurious character of their operations is well illustrated on ]jlates 52, 

 53 and the rapid ]irogress these pests ma\' make; is shown in tiL(iu'es 1 

 and 2 of plate •:,;'^. iMgure i was taken .Sep. 2S, 1901 and figure 2 of the 

 same trees was taken ,\pril igo2. It will he seen lh;U these; i)ines have 

 been practically killed within a year and if a close examination is made we 

 will find conditions substantially as follows: 



At the ver)' i)ase of tlu; trees there are a number of irregular, rather 

 large masses of pitch and on remo\ing these it will be found that they 

 cover the entrance to a gallery about '^. inch in diameter. The condition 

 within is well re])resented on plate 58, figure 4, which shows the preserva- 

 tion of the walls by the inliltration of ])itch and is thus incontrovertible 

 evidence of living tissues having been attacked. This borer, known as 

 Dendroctonus terebrans Oliv., is a very common species in XCw 

 \'ork .State where it may be met with in small numbers in almost an)' pine 

 irrove. It can hardiv be regarded as a dangerous form though it works in 

 living tissues. I'"arther uj) the same trees a much more serious injury is 

 evidenced by the numerous pilch tuljes on the bark [pi. 54, fig. 2 |. Plate 

 54, figure 4, represents one in profile. The remo\al of a piece of bark 

 will show the condition of aftairs under the pilch tube. Plate; 54, figure 

 3, illustrates the large central chamber underneath with five longitudinal 

 galleries leading therefrom. Small notches may be ol)served on the sides 

 cf these galleries, particularly near the extremiti'-s, ai.d these lead into 



333 



