February, '17] LAMSON: MERCURIAL OINTMENT FOR HEN LICE 71 



a protection of 69.1 per cent, but all the oil mixtures averaged 85.9 

 per cent. 



17. Though the trees were retouched, treatment was less effective 

 the second year than the first, the average protection the second year 

 being 7.7 per cent as against 82.1 per cent for the first. 



18. Up to a certain age, it appeared that asphalt varies in efficiency 

 inversely as the age of the tree. In other words, the older the trees 

 the less efficient the treatment. 



As a result of our investigations at Berryville, we concluded that the 

 most practical manner of handling the borer properly is by worming 

 the tree at the right time every year. 



Summary 



1. That the protection offered by white lead is not commensurate 

 with returns. 



2. That pruning compound is worthless as a borer protector. 



3. That paper wrappers and wooden veneers, from first observa- 

 tions, appear to be impracticable. 



4. That the cost of screening is too great to warrant its use as a borer 

 protector. 



5. That the use of asphaltum is attended with injury and that 

 its efficiency as a borer protection is not worthy of the risk to the 

 trees. 



6. That worming the trees during the months of August and in 

 early September is the most practicable as well as the cheapest method 

 for the controlling of the borer. 



Vice-President G. A. Dean: If there is no discussion, we will now 

 listen to a paper by Mr. George H. Lamson, Jr. 



MERCURIAL OINTMENT, AN EFFECTIVE CONTROL OF 



HEN LICE 



By G. H. Lamson, Jr., Storrs, Conn., 



Insecticides, such as the arsenate of lead, lime sulphur, hellebore, 

 hydrocyanic acid gas, carbon bisulphide and nicotine solutions, are of 

 known value and it is from these that the economic entomologist 

 usually draws for the direct control of insects. 



To most of you the problems of the control of insects affecting the 

 products of the orchard, field, forest and garden are of most interest, 

 though from time to time your attention is directed to those animal 

 parasites that are of much economic importance. 



