MAY 107 



XVIII 



Warm as is the welcome oifered by us to American 

 visitors to our shores and bright as are our 

 hopes for the permanence of the entente 

 cordiale to which the United States form the latest 

 accession, it must be admitted that there are certain 

 products of that great country for which we have no 

 use whatever. One of these is the great larch sawfly 

 {Nematus Erichsoni) which first made its presence in 

 this country conspicuous among the fine larch woods 

 of Cumberland in the summer of 1906, and thereafter 

 wrought most serious havoc there and elsewhere. 



This pestilent insect bores into the young growth of 

 the larch with its saw-like ovipositor, inserting its eggs 

 under the bark. About the middle of May the cater- 

 pillars appear — little green devils with black heads — and 

 set to work to strip the foliage. If unchecked, the fly 

 multiplies so prodigiously that the whole woodland 

 stands brown and sere at midsummer. Many of the 

 trees, especially young ones, succumb to the attack in 

 a single season, dying outright ; while those that sur- 

 vive are so greatly debilitated as to become the prey 

 of the deadly larch fungus Dasyscypha. Several land- 

 owners, despairing of resistance to such hordes of 

 caterpillars, felled their larches over many hundreds 

 of acres. Many devices were gravely recommended for 

 combating the scourge, such as spraying the trees 

 when the caterpillars are newly hatched, collecting the 

 cocoons when they descend into the grass in June, 

 smoke from fires kindled under the trees, and so forth. 



