68 THE HOUSE FLY 



this burns, a pungent vapour will rise to the ceiling. Retire 

 and close the door for the night. Next morning the flies 

 will all be lying dead on the floor, and may be swept up. 



Pyrethrum powder is the base of the ordinary insect 

 powders. The latter may be used, but they are usually 

 either adulterated, or weak owing to age, or the grinding 

 up of the stems of the plant with the flowers. If these 

 insect powders are employed, two teaspoonsful should be 

 employed for an ordinary sized room. If the flies are not 

 killed after the first experiment with the pyrethrum 

 powder, increase the dosage. Pyrethrum powder is made 

 by grinding up the dry flower-heads of a plant known as 

 the Pyrethrum cineraria folium. When freshly ground the 

 powder is strongest in its action. The dry flower-heads 

 or powder may be had of any chemist. Failing a supply of 

 the flower-heads or powder, use Keating's Insect Powder. 



There are various kinds of fly traps and fly poisons on 

 the market, all of which are more or less effective in ridding 

 houses temporarily of flies. Paper smeared with a resinous 

 sticky substance such as Tanglefoot is excellent. Many 

 people object to its use owing to its stickiness. However, 

 with ordinary care there is no danger of it getting blown 

 with its sticky side on to furniture, the carpet, &c. It ought 

 to be fastened with drawing pins to a piece of board or 

 stiff cardboard, and removed and burnt when it is smothered 

 with flies,, or when it gets too dry to hold them. 



Flies are fond of sitting on vertically hanging cords. 

 Advantage is taken of this habit to smear cords or strips 

 of tape with bird lime or other kinds of adhesive. These 

 are obtainable from grocers and ironmongers. 



The wire cage trap is another effective means of catching 



