1913 ENTOMOLOGICAL SOCIETY. 91 



There was an interesting outbreak this season in some of the St. Lawrence 

 Island parks of Elaphidion villosum. Thousands of branches of oaks were broken, 

 some hanging to the trees, and others scattered about the ground. These branches 

 were gathered and burned. This will probably prevent a recurrence next year. 



Saperda calcaraia is a very destructive enemy of poplar in. the east and also in 

 Manitoba. Throughout parts of the east it is particularly difficult to preserve poplar 

 shade trees on account of its ravages. It infects the trunk and larger branches, and 

 I have taken it from the heart of the largest balsam poplars. Very careful in- 

 spection and removal of the borers in the fall may prevent injury to valuable shade 

 trees, and the older grubs can be removed with a knife or killed by benzine or car- 

 bon bisulp'hide injected into their borings. 



Agrilus anxius. This injurious species is very destructive to imported white 

 birches about Ottawa. Native birches appear always better able to resist its attack. 



Mr. Caesar: Have lyou ever discovered on pine branches swellings from 

 half an inch to an inch and a half in diameter due to a species of Peridermiwm 

 probably P. cerebrum? In parts of Lambton County pine trees are being injured 

 by this disease. 



Mr. Swaine : Yes, in the West, on jack pine and mountain pine and, in the 

 east, on jack pine, such Perider?niuni galls are very common. 



Dr. Walker: Have you seen anything of Retinia on pine this year? 



Mr. Swaine: Yes. It has been rather common in the West, particularly 

 in the Eocky Mountain reserve. Alberta. Its work is usually found more or less 

 commonly throughout our eastern forests, but I have no record of special outbreaks 

 there this season. 



Dr. Walker: Mr. J. H. White of the Dept. of Forestry, University of 

 Toronto, sent me a number of twigs of jack pine infested with a species of Eetinia, 

 from Sudbury, Ont., where he said iihey were very abundant. 



Dr. Hewitt : I was very glad that Mr. Swaine emphasized the question and 

 discussed the importance in the control of the Larch Sawfly, of transporting the 

 parasitic enemies from one locality where they are extremely abundant, to another 

 locality where the attack of the sawfly is not so severe. This has been done in the 

 case of a number of other insects which we know. About five years ago I recom- 

 mended and also started in England a system such as Mr. Swaine suggests, of 

 aiding the natural control of the Larch Sawfly, and I believe the Board of Agri- 

 culture in England have continued it. The method I recommended is this: I 

 made a careful study of the percentage of parasites and the increase. If an 

 increase in parasitism was observed sufficient, as I believed, to be of material 

 assistance in obtaining control, cocoons were to be collected and transferred to 

 localities where an outbreak of the sawfly was in the incipient stage. This seems 

 to be the only possible alternative to the introduction of parasites from outside and 

 is one which could very well be adopted. What must be done in these cases, 

 however, is to keep a very close watch, as Mr. Swaine suggests, on the outbreak 

 from time to time when it begins and notice from year to year how the parasites 

 increase in abundance. This is the method I adopted in England. From year to 

 year the percentage of parasites increased, and as it increased it showed that the 

 control of the natural parasites was very efficient. I hope that we shall be able to 

 carry on some experiments in this country on these l;nes. 



