1900 



ENTOMOLOGICAL SOCIETY. 



35 



In West Virginia it has been found that there is a proper time to fell trees to pre- 

 vent damage by insects. Dr. Hopkins cut different kinds of trees twice a month year 

 after year, and he got definite results for the oak and hickory for example. The timber 

 cut in the winter months was gradually converted into a powder, while that cut during 

 the summer remained almost intact. Theae results are confirmed in the practical opera- 

 tions in the forests, for it has been observed that certain species of trees felled in late fall, 

 winter, or early spring suifer more damage than those felled in July and August. 



Fig. 1. Hylurgua piniperda. 



Fig. 2. Hylesinus fraxini. 



Fig. 3. Scolytus destructor. The beetle, 

 magniiied, and its burrows. 

 (See page 72. ) 



Again, much has been learnt re 

 garding the disposal of timber which 

 has become afi'ected.and the influence 

 of lumbering methods and forests tires 

 on the general problem of insect de- 

 predations. It is a matter of obser- 

 vation that unhealthy, weakened, 

 dead trees are the most likely ones to suflfer from insect attacks. Thus careless methods 

 of handling timber whereby standing trees are girdled, branches broken, and otherwise 

 dismembered and disfigured, are very fruitful sources of insect; distribution to thoee 

 areas. These infested areas become centres of infestation to the surrounding forest. 

 In Ontario where lumbering operations are carried on in many isolated limits the 

 danger is extremely great. The trees along the margin of the fellf^d areas are very 

 liable to lose their vitality on account of their inability to adapt themselves to the 

 changed conditions which have arisen. If the lumbering operations are postponed for 

 any length of time there is a great likelihood that the insects will spread from the felled 

 areas to the unbroken forest, but where lumbering is carried on continuously in an area 

 the insects find sufficient nev- felled timber and branches without betaking themselves to 

 the unbroken forest. 



The plan of forest-ranging for the prevention of fires is undoubtedly of tremendous 

 value in the prevention of the spread of forest insects, but there is another work for the 

 ranger. He could, if he knew more about insect conditions and habits, arrange for the 



