419 



cases by the use of compressed air for cleaning out machinery and 

 all cracks and crevices in floors and walls, and by the treatment of 

 the floors at regular intervals with gasoline or kerosene ; while the 

 latter includes the careful inspection of used sacks, which should be 

 thoroughly cleaned or fumigated before being taken to the store- 

 room. 



Difficulties in the way of fumigation by means of carbon bisulphide 

 may arise owing to underwriters refusing to insure against risks 

 from fire if this material is on the premises, and in the case of hydro- 

 cyanic acid gas, either the building is not sufiiciently air-tight for 

 fumigating, or the stored food contains too much moisture to render 

 the process practicable. The best method involves the construction 

 of small fumigating rooms about 8 X 10 ft. where a temperature of 

 from 130°-140° F. can be maintained for several hours, the destruction 

 of the pests being effected by means of heat alone. 



Swain (A. F.). Fumigation Experiments : the Time Factor. — Jl. Econ. 

 Entom., Concord, N.H., xi, no. 3, June 1918, pp. 320-324. 



From a series of 44 experiments on a total of 7,485 insects carried 

 on in the day-time with models of trees covered with tents, in which 

 both CoccinelUds (Hippodamia convergens) and red scale {Chrysomphalus 

 aurantii) were experimented with, it was shown that an exposure 

 to hydrocyanic acid gas for 30 minutes was not sufficient to obtain 

 the highest killing efficiency. It was found however, that with 

 45 minutes as good results were obtained as with 60 and 90 minutes. 

 From an examination of the results of commercial fumigation against 

 Coccus citricola (citricola scale) in 125 groves during the 1917 season, 

 it was learned that there was no practical difference between the kilfing 

 efficiency of the hydrocyanic acid gas with exposures of 45, 50 and 

 55 minutes. 



It may therefore be concluded that under normal conditions for 

 commercial fumigation, a 45 minute exposure is fully as efficient as 

 one of 50 or 55 minute. 



Severin (H. H. p.). a Native Food-Plant of RhagoJetis fausta, O.S. — 

 Jl. Econ. Entom., Concord, N.H., xi no 3, June 1918, pp. 325-327. 



Rhagoletis fausta (northern or black-bodied cherry fruit-fly) is a 

 serious pest of cultivated cherries, but one which in Ontario has not 

 been found to cause injury to any of the native wild varieties of cherry, 

 but only to the imported ones, or those that have grown up wild 

 from the seeds or roots of these. Since this Trypetid occurs in the 

 alpine regions of the White Mountains, its natural food-plant would 

 obviously seem to be species of wild cherry or plum, or the berries 

 of some species of Berberis or Lonicera, especially since the larva of 

 R. cerasi (European fruit-fly) fives in cherries, Lonicera xylosteum 

 and Berberis vulgaris. 



An examination of Pruniis pennsylvanica, L. (wild red, bird, fire 

 or pin cherry), showed that most of the fruit had been punctured 

 by insects, and when ripe, about a quart of these wild cherries were 

 scattered in steriUsed sand in jars towards the end of July. During 



