266 Rkpokt of the 1)i:i'autm1':int of Entomology of thb 



character op hydrocyanic acid gas. 



Hydrocyanic acid gas may be generated by bringing cyanide of 

 potassium in contact with sulphuric acid. It is colorless, has a 

 faint odor of almonds, and when inhaled, unless largely diluted 

 with air, is very dangerous. Much care should therefore be 

 used in handling it. 



CLASSIFICATION. 



The experiments were divided into two series. Series I 

 included the experiments with uninfested buds and Series II the 

 Hxperiments with the hibernating scales. 



SERIES I. EEFEOT OF THE GAS UPOIN BUDS. 

 The following experiments with buds of a variety of fruits 

 were undertaken to ascertain if possible whether bud sticks 

 could be safely fumigated with the gas strong enough to kill the 

 scale. The conditions were not entirely satisfactory as the 

 treatment was somewhat delayed and the treated buds were not 

 set in until the first week of August. This was out of season 

 for most of the varieties. Also the treated buds were not set 

 in until after the checks, which were budded at the proper time, 

 and were placed about four inches above them where they were 

 too high to be protected by the earth thrown against the trees 

 during fall cultivation. In addition to this they were neces- 

 sarily placed on the furrow sides of the trees thus endangering 

 them to injury during cultivation. These unfavorable condi- 

 tions must be in part, and probably in large part, the cause for 

 the failure of the treated buds to set or grow, on the average, 

 equally as well as the checks. 



