1921 ENTOMOLOGICAL SOCIETY. 27 



A good example of this point was seen this summer. A section Of winter 

 range situated on the banks of the Fraser river was observed. For five miles 

 outside this winter range fence the range was swarming with the injurious species 

 of locusts and no Bunch-grass was visible. In many places the grasshoppers were 

 present at the rate of from fifteen to thirty to the square yard. Immediately 

 inside the barbed-wire fence was a fine stand of Bunch-grass, in places higher than 

 one's waist and showing no signs of grasshopper injury. Ten yards inside the 

 fence there were about five grasshoppers to the square yard; at twenty only an 

 occasional specimen of the injurious species could be found, but a few of the 

 species typical to Bunch-grass land were seen. At the time that these first obser- 

 vations were made the injurious species were confining their attention to the 

 young green grass shoots which were plentiful on the open range. The barbed-wire 

 fence seemed literally to be a barrier, the choice of food keeping them outside. 



A few weeks later, on July 30th, after the drought had set in, this area was 

 again visited. In riding across the main range it was noticed that there were now 

 no green shoots coming up and the grasshoppers had cut down all the standing 

 grass, which was lying about on the ground as before described. As the winter 

 range was approached the grasshoppers became markedly scarcer, especially was 

 this the case with Camnula pellucida, a habitually migratory species. On reaching 

 the winter range a distinct change could be seen, particularly just inside the 

 fence. On entering the winter range it was found to be swarming with the 

 injurious species of grasshoppers which were working in from the open range 

 outside. The Bunch-grass plants presented a broken, ragged appearance, and the 

 ground beneath the plants was strewn with pieces of stalk and leaves which had 

 been bitten off. 



As one advanced further into the winter range the damage became gradually 

 less and less apparent, until at about 300 yards from the fence hardly any of the 

 injurious species could be found. The spell of dry weather was unusually severe 

 this year and the grasshoppers being more numerous than hitherto recorded in 

 this locality, the damage to winter ranges was of considerable importance. As well 

 as spreading into the winter ranges the grasshoppers entered the timber and ate 

 the timber grass and the Aspen leaves, and could be found in some places to have 

 penetrated to a depth of two miles. Towards the end of August some very heavy 

 rains occurred, and in the course of a week the range was a sheet of green again 

 instead of a dead brown. Every grass plant had sent up a number of new tender 

 shoots. 



As soon as this occurred the majority of the grasshoppers deserted the dry 

 Bunch-grass of the winter ranges and the timber, and went out on to the main 

 ranges again. They were on the decrease by this time, and were quite incapable 

 of keeping down the new grass. The cattle, it was also noticed, left the timber at 

 this time and worked out on to the open ranges again, where they had an abundance 

 of good green fall feed. 



It may be understood from what has been said that overgrazing of a range 

 bears a very important relation to the increase of the locusts. Overgrazing causes 

 the disappearance of some species of grasshoppers, while it favours the increase of 

 others. The species which benefit by the overgrazing are unfortunately the most 

 destructive species found in British Columbia. ISTot only does the overgrazing of 

 a large area favour the increase of some species but it may even change the habits 

 of oviposition and feeding of some of those species. 



