208 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
a strong factor in creating local frost areas. Open spaces should always be left 
through windbreaks in depressions and on the lower sides of partly enclosed 
fields, so as not to hinder the movement of cold heavy air from high to low 
elevations. — M. L. H. 
Wood-boring Insects, A New Mixture for Controlling : Sodium Arsenate 
Kerosene Emulsion. By F. C. Craighead (Jour. Econ. Entom. viii. Dec. 1915, 
p. 513).— Tests made on Goes (work similar to Prinoxystus and Cyllene pictus) 
showed that whilst kerosene emulsion penetrated the wood and galleries it was 
seldom in sufficient quantity to kill the larvae. 
The result of trials with the addition of a 5 per cent, to 10 per cent, arsenical 
solution were, however, highly successful. The mixture is applied to the holes 
where the boring dust exudes, and the solution quickly ascends along the sides 
of the burrow and through the frass, often to a distance of 10 or 12 inches, killing 
the larvae in a few days. The remedial measure is equally efficacious on seasoned 
wood as when applied to living trees. — G. W. G. 
Woolly Aphis. By E. N. Cory (Jour. Econ. Entom. viii. p. 186, Apr. 1915). — 
Experiments were made to exterminate the woolly aphis by soil treatment with 
soluble oil (1 : 15), scalecide (1 : 15), Electro Insecticide soap (1 lb. to 4 gallons 
water), lemon oil (1 : 24), Nico-sul (1 : 240), lime sulphur (1 : 9), undiluted pine 
tar creosote (i£, 2, or 3 quarts to a tree), kerosene emulsion (10 per cent.), tobacco 
dust (i£ to 3 lb. to a tree), apterite (1 lb. 3 oz., 2 lb. 6 oz., and 4 lb. 12 oz. to a 
tree). Only the pine-tar creosote treatment was successful. Undiluted all the 
aphides were killed ; in 6 per cent, emulsion most were killed. All the materials 
used were applied in a trench dug round the roots of the affected tree. The 
creosote had a remarkably persistent odour, its smell being apparent 21 months 
after its application. The author noticed the ant, Lasius interjectus, in close 
connexion with the aphis and suspects it to be instrumental in spreading it. 
