1920 ENTOMOLOGICAL SOCIETY. 77 



liiiiate, but possibly from its repellent action, which causes the larvif to wander 

 away from the plant and thus perish. Larva", however, once M^ell inside the plant, 

 do not seem to be affected. 



3. Does it Kill the Pupae? Three tlov.er pots filled with fine sandy soil 

 were sunk in the soil this spring and then thoroughly saturated with corrosive 

 sublimate. Pot 1 contained 100 puparia and was saturated with 1-1,000 strength. 



Pet 2 contained 100 puparia and was saturated with 1-1,000 strength. 



Pot 3 contained 35 puparia and was saturated with 1-240' strength. 



Eight other pots containing in all 885 pupae were left untreated and served 

 as checks. 



Pesults. 



Pot 1 of the treated pui)aria gave an emergence of 11 flies. 



Pot 2 of the treated puparia gave an emergence of 47 Hies. 



Pot 3 of the treated puparia gave an emergence of 2 flies. 



Total emergence from treated pots (!0=25.5 per cent. 



From the 885 pu])ae in the checks 174 flies, or 19. G per cent, emerged. We 

 can therefore only conclude that corrosive sublimate does not kill the pupae. 



Incidentally it may be mentioned that from the 885 untreated pupae, 424 

 cynipid and 15 staphylinid parasites emerged, and from the 335 treated puparia 

 20 cynipids and 1 staphylinid. 



THE PRESENT STATUS OF MILL-INFESTIXG PESTS IN CANADA. 

 E. H. Strickland, Entomological Bkanch, Ottawa. 



The Entomological Branch of the Dominion Department of Agriculture is 

 undertaking a series of investigations and experiments upon the control of the 

 insect and other pests of flour mills, bakeries, elevators and warehouses. This has 

 necessitated a preliminar}^ visit to representatives of these various industries 

 throughout the Dominion for the purpose of ascertaining what are the most im- 

 portant pests, and the effectiveness of methods already in operation im- their 

 control. 



In so far as the flour mill? are concerned one pest, namely, the Mediterranean 

 Flour Moth {Ephesiia kuelinldla), so far exceeds all other classes of mill pests in 

 the trouble it causes, that the majority of millers look upon it as the only one merit- 

 ing serious consideration. One of the favorite breeding places of this pest is inside 

 the legs of conveyors, where the larvre spin a voluminous mass of silk, which 

 collects large quantities of flour and dust. If no precautions are taken this, in 

 time, entirely clogs the elevator, which must then be dismantled and thoroughly 

 cleaned. 



One other group of mill pests — the Flour Beetles (Triboliuia spp.) — is almost 

 as prolific in Canadian mills as is the moth, but since these beetles do not interfere 

 with the milling process they are, unfortunately, inclined to be tolerated in the 

 various parts of a mill which they inhabit. From the millers' point of view this 

 is readily understood. The moth is a serious menace to the smooth running of 

 the mill. Ilencro its control is of great, sometimes even of vital, importance to 

 the operation of an infested mill. The beetles on the other hand do not incon- 

 venience the miller, and they are readily sifted out of flour, which apparently 



