4 FIRST REPORT ON ECONOMIC BIOLOGY. 



been previously dipped in a strong- solution of Paris green, should be 

 placed amongst the plants at night and covered with a cabbage leaf. 

 The following morning the dead millipedes should be removed, and the 

 trap reset. 



In flower beds, dig out a hole sufficiently large to contain the 

 fist and wrist ; fill with bran and cover with water. After two or three 

 days pour on to the bran boiling water. The contents of two such 

 holes were carefully counted after treatment, and were found to con- 

 tain 2,448 and 1,793 dead millipedes respectively. 



THE BULB MITE. 



Rhizoglyphus echinopus, F. & R. 



Considerable loss and disappointment has been occasioned by the 

 prevalence of this mite during the past year. 



In my 5th Report I mentioned that I had carried out a number 

 of experiments on bulbs by soaking and spraying them with various 

 fluids, such as paraffin and turpentine emulsions, sulphide of potassium, 

 etc. , but none gave satisfactory results. Many of the mites were 

 killed, but sufficient numbers remained alive to complete the destruc- 

 tion of the bulb. 



Since then, my attention has been called to a statement made at a 

 meeting of the Scientific Committee of the Royal Horticultural Society 1 

 by Mr. Saunders, which reads as follows : 



;< When bulbs are thus infested with these mites nothing can be 

 done to save them. Where only a few mites are at the base of the 

 bulb, where the attack g-enerally commences, they may be killed 

 by immersing- the bulbs for five minutes in water 1 at a temperature of 

 115 to 120 Fahr. If some sulphide of potassium (6 oz. to the pint) 

 be added to the water, this remedy would be all the more efficacious ; 

 indeed it is said that soaking the bulbs in this solution cold for twenty 

 minutes will kill the mites." 



I was particularly interested in the concluding statement as I 

 had experimented largely with potassium sulphide, but never so strong 

 as recommended in the above statement. I therefore decided to repeat 

 my experiments using three strengths of potassium sulphide, viz. : (i) 

 4oz. to i pint of water; (2) 6 oz. to i pint; and (3) 8 oz. to i pint. 



Very badly infested bulbs were placed in the solution No. i, and 



iGard. Chron., 1902 (Dec. 20), p. 465. 



