

ANIMALS INJURIOUS TO FARM AND GARDEN PRODUCE. 5 



allowed to remain for an hour and a half; in solution No. 2 they 

 remained for one hour ; and in solution No. 3 for fifteen minutes. 



Upon removing- the bulbs, three in each case, two were placed in 

 water, and the leaf scales separated and thoroughly picked to pieces, 

 and the mites, which floated on the water, were then carefully removed 

 and placed on glass slips and examined under a low power of the 

 microscope, the third bulb was cultivated in order to test if the solution 

 had in any way injured it. 



In the cases i and 2 quite 90 per cent, of the mites were destroyed, 

 but not more than 25 per cent, in No. 3. All three bulbs were culti- 

 vated, numbers i and 2 grew and flowered, but No. 3 grew for a short 

 time only, then died. 



From the above experiments I am of opinion that soaking the 

 bulbs for an hour or more in 4 to 6 oz. of potassium sulphide mixed 

 with i pint of water, will destroy by far the larger proportion of the 

 mites. The length of time the bulbs are allowed to soak seemed to 

 be of more importance than the actual strength of the solution, for 

 no difference could be observed in those soaked in solution No. i 

 from those in No. 2. 



Since these experiments were made it has occurred to me that it 

 might be profitable to try watering bulbs, after being treated as 

 described above, with weaker solutions of potassium sulphide, after 

 they have been potted or planted out. 



COLLEMBOLA AS INJURIOUS INSECTS,* 



In a communication read at the Oxford Meeting of the Associa- 

 tion of Economic Biologists, 1 I drew attention to the part that various 

 species of Collembola play as injurious insects, and instanced many 

 cases reported by Carpenter, 2 Curtis, 3 Ormerod, 4 Murray, 5 Guthrie, 6 

 myself, 7 and others, where they were the direct cause of damage to 

 roots and seeds of healthy plants, and I incidentally pointed out, in 

 referring to the nature of the injury, that they also play an important 



* Reprinted from the Journ. Econ. Entom., 1910, pp. 204, 205. 



ijourn. Econ. Biol., 1909, vol. iv, pp. 83-86. 



2 Proc. Assoc. Econ. Biol., 1905, vol. i, p. 14. 



3 Farm Insects, p. 432. 



4Rpt. Obs. Inj. Insects for 1904, p. no. 



"'Economic Entomology, Aptera, p. 404. 



6 The Collembola of Minnesota, 1903, p. 4. 



1 Rpt. on Inj. Insects for 1905, p. 10. 



