278 NEW YORK STATE MUSEUM 



beetle's work though this is not usually observed till the trees begin to die 

 at the top from no apparent cause. Examination of the infested bark may- 

 reveal parental galleries i to i ^^ inches long with diverging, dilating larval 

 galleries and if the brood has completed its transformations, portions of 

 the bark will be dotted with holes, such as might be made with no. 8 buck- 

 shot, through which the beetles have escaped. 



Natural enemies. This insect has a number of natural enemies but 

 unfortunately in the case of the Geneseo outbreak they appear to be rela- 

 tively scarce. There are three very small four winged flies which breed on 

 the grubs in their galleries. They bear the scientific names of .S p a t h i n a 

 trifasciata Riley, S. uni fascia tus Ashm., and Lysitermus 

 scolyticida Ashm. We obtained examples of the Spathius from 

 infested wood from Geneseo. Another four winged fly known as Brae on 

 scolytivorus Cress, also breeds in this insect and appears to be one of 

 the forms we reared. A predaceous bark beetle, C 1 e r u s i c h n e u m o n e- 

 us Fabr., preys on this species and is probably the form we found in 

 association with this borer. 



Remedial measures. Previous records indicate that such attacks may 

 extend over a series of years and result in the death of a very large propor- 

 tion of the trees in a locality, and nothing but the prompt execution of 

 drastic measures over the entire infested area would avail much when the 

 pest is abundant over large areas. It has been shown that the insects 

 spend most of their lives boring the inner bark and outer sapwood and 

 are therefore mostly within the tree and hence inaccessible to attack unless 

 the trees are cut and the infested bark removed. It is not enough to simply 

 cut the trees. The removing of the bark w^ill cause the death of most of 

 the borers but more thorough work will be accomplished by burning the 

 infested limbs and trunks before the beetles emerge in June. Thoroughly 

 infested trees and affected portions of others are doomed and therefore it 

 can hardly be considered a loss to cut them at once while a great risk is 

 taken if they be allowed to remain, thus rearing hosts of beetles which 

 may be expected to attack other trees the following summer. The more 



