1917 



ENTOMOLOGICAL SOCIETY 



125 



and tlR'ir being nu tliirereuce as far as could be detected between tlie checks and 

 those under experimentation. In the cheeks the larvae were actively at work and 

 their abundance was indicated liy the amount of sawdust exuding from the numerous 

 burrows. All tiie trees treated with different strengths of scalecide showed just as 

 high a ])ercentage of infestation as the cliecks. This preparation had no appreci- 

 able eil'ect. In the trees treated with carbolineum, either pure or as an emulsion, 

 not a trace of infestation could be found. After searching for several hours one 

 shrivellod and blackened larva was discovered in its burrow. However, it was not 

 desirable to injure the trees too much by cutting into all sus])icious egf[; punctures. 



The girdling work of the larvae on 

 nursery trees. 



Showing the beginning of the forma- 

 tion of the pupal chamber. 



This experiment was again carefully examined on June 18 and confirmed 

 prc\ious observations. The checks and those treated with scalecide were nearly all 

 badly infested, many trees with as many as eight to ten borers present, while a few 

 both in the treated and checks were apparently free. Those trees treated with 

 carbolineum and its emulsion were growing even more vigorously than the un- 

 treated ones, and not a single trace of the work of the borer in any one of the twelve 

 treated trees could be discovered. These preparations colored the trunks of the 

 trees a beautiful bro\vn, but other than that no injury could be seen. 



Fearing that such a perfect control might be due to other causes than the effect 

 of the treatment, a larger series of experiments was planned for the fall of 1914 

 and spring of 1915. Discarding the miscible oils, kerosene emulsion was given a 

 trial as it has been recommended for the control of the locust borer (Cyllene 

 robinio'). In a l)lock of over 10,000 trees ready for digging in the fall of 1015 



