347 



poisons used in combination with various fungicides shows that the 

 toxic action is reduced by barium tetrasulphide aiid sodium sulphide 

 used together (by G'i per cent.), by hme-sulphur (by 19'2 per cent.), 

 and by Bordeaux mixture (by 43'5 per cent.), while on the other hand 

 it was increased 13'1 per cent, by the use of sodium sulphide. It is not 

 yet determined whether this action of sodium is due to the increased 

 palatability of the leaves on which the insects feed voraciously, or to 

 the chemical reaction resulting in the formation oi sodium arsenate 

 and a metallic sulphide. 



Brittaix (W. H.). Sucking Insects and Mites injurious to the Apple 

 and Pear. — Nova Scotia Coll. Agric, Truro, Circ. no. 17, 1917, 

 15 pp. [Received 4th June 1917.] 



This circular briefly notices and recommends controls for the 

 following sucking insects : — Lygus communis var. novascotiensis (green 

 apple bug), [see this Review, Ser. A, iv, pp. 96, 520, and v, p. 194], 

 L. pratensis (tarnished plant bug), Lygidea mendax (false apple red bug), 

 Idiocerus fitchi, Van D. (black apple leaf -hopper), Emjpoa rosae, L. (rose 

 leaf-hopper), Empoasca mali, Le B. (apple leaf-hopper). Aphis pomi, 

 De G. (green apple aphis), A. sorbi, Kalt. (rosy apple aphis), Aphis 

 (Siphocoryne) avenae, F. (grain aphis), Eriosoma lanigerum, Hausm. 

 (woolly apple aphis), Lepidosaphes ulmi, L. (oyster-shell scale), Psylla 

 pyricola, Forster (pear psylla), Eriophyes pyri, Pgst. (pear-leaf blister 

 mite), and Phyllocoptes schlectendali, Nal. (apple leaf-mite). 



Brittain (W. H.). Legislation in Force in Nova Scotia to prevent the 

 Importation and Spread of Insects and Diseases injurious to Plants. 



— Nova Scotia Coll. Agric, Truro, Circ. ]io. 23, 1917, pp. 12. 

 [Received 4th June 1917.] 



The legislation here noticed has already been recorded [see this 

 Review, iii, p. 71]. To the list of the insects subject to the Act, the 

 names of two additional species, Rhagoletis cingulata and R. Jausta. 

 (cherry fruit-flies), are added. 



Hewitt (C. G.). The Introduction into Canada of the Ichneumon Fly, 

 Mesoleius tenthredinis, a parasitic Enemy of the Larch Sawfly, 



Nematus erichso7iii. — Agric. Gaz. Canada, Ottawa, iv., no. 5, May 

 1917, pp. 355-357, 1 fig. 

 Followmg on the destruction of the tamarack or larch trees throughout 

 Eastern Canada a few years ago owing to heavy infestation by Lygaeone- 

 mufus (Nematus) erichsoni (the larch sawfly), the plan was adopted 

 of importing cocoons of this sa^^^y parasitised by Mrsoleius tenth- 

 redinis, an Ichneumouid which controls this pest in Europe, 

 whence the sa■\^'fly had been introduced into Canada. This paper 

 describes the introduction and establishment of the parasite, which 

 was begun in 1911. In 1913, larch sawflies, which were abundant in a 

 larch swamp where the parasite had been distributed, were found 

 parasitised to the extent of 68 per cent. Hypamhlis albop ictus and 

 Microcryptus labralis, other parasites of L. erichsoni were also found 

 on this occasion. By the spring of 1916, 31. tenthredinis had become 

 thoroughly established, and affords proof of the success of biological 

 methods of control for certain insect pests. 



