112 First Report on Economic Zoology. 



upon the moss surrounding growing orchids, it is quite possible to raise 

 it and transfer it to very small pots, so that if we have the means of 

 preventing the depredations of these Spring-tails over a small area a great 

 deal would be accomplished. 



Apologising for troubling you,' etc., 



(Signed) Jeremiah Colman. 



Fumigation under Glass for Mealy Bug and 



other Pests. 



Frequent enquiries have been made as to the use of hydrocyanic 

 acid gas under glass for the destruction of Mealy Bug. This treat- 

 ment will be found to far surpass the old methods of fumigating with 

 tobacco and various patent compounds. 



The method of fumigating with hydi'ocyanic acid gas (HCX) for 

 Mealy Bug, Scale, etc., under glass, is as follows : — 



For every 1,000 cubic feet of space use 5 ozs. sulphuric acid, 8 ozs. 

 water, 3 ozs. cyanide of potassium. 



The water should be put into a jar and then the acid added to it ; 

 remember to always add the acid to the water, and not the water to 

 the acid ; the cyanide should be in small lumps and WTapped up in 

 blotting-paper ; the cyanide is then dropped into the jar of water and 

 acid and the fumes allowed to generate for an hour. It, of coui'se, 

 has to be done quickly and with care, owing to the poisonous fumes 

 being so deadly to all forms of animal life. The cyanide should be 

 dropped into the acid and water from outside the house ; this can 

 easily be done by putting the jar close to the door or window, so that 

 it can be shut as soon as the packet of cyanide touches the mixture. 

 AVhen wTapped in blotting-paper, some seconds elapse before the 

 fumes generate. 



If the glass-house is more than 10,000 cubic feet another jar will 

 be required, and for every additional 10,000 feet. 



The foliage of all plants to be treated should be as nearly dry as 

 possible. 



The temperature never more than 60° Falu'. 50° Fahi\ is the best 

 temperature. At heat over 50° Fahr. there is a risk of harming the 

 foliage. 



Do not fumigate in a strong light, as foliage may then be 

 damaged ; fumigate always after sunset. 



Do not fumigate vines when in bloom or just before the grapes 

 have commenced to ripen. 



