70 THE BEEOKT OF THE No. 36 



tive control measure, whenever it has been undertaken in an efficient manner. 

 While much dyking has been done, huge breeding areas remain unreclaimed and 

 produce little but mosquitoes. An aerial survey is to be undertaken next year to 

 map out the unreclaimed areas capable of flooding, and it is believed that when 

 these large breeding places have been dealt with, the mosquito pest will cease to be 

 a source of misery and financial loss to the inhabitants of the affected parts of the 

 Talley. 



Other Southern British Columbian Mosquito Problems. 



During the past two years a number of brief surveys of mosquito conditions in 

 other parts of British Columbia were undertaken. The Columlbia valley, the Arrow- 

 lake district, the Sloean valley, the Osoyoos valley and other places were visited. 

 Although the details of the problem, the species involved, and the intensity of the 

 pest at different places varied considerably, the basic factors in the problems ap- 

 peared much the same, the flooding of breeding areas through the quick melting of 

 the snow at the mountain sources of the rivers. Aedes vexans was found to be a very 

 constant species, but the fauna of the different valleys varied consrderaibly ; Aedes 

 punctor replaced Aedes aldriclii as the dominant species in the more deeply wooded, 

 less developed valleys, while still other species, not found in the Lower Eraser 

 Valley, were dominant in the drier, more arid regions. As the surveys were very 

 brief and incomplete, these species will not be dealt with here, but enough has been 

 said to indicate the enormous field for valuable research that British Columbia offers 

 to those interested in the study of Mosquito Control. The problems are of vast 

 importance and their satisfactory solution can only he arrived at as a result of care- 

 ful fauna! and topographical investigations. 



REPORT ON INJURIOUS INSECTS IN QUEBEC DISTRICT FOR 1920. 



Georges Maheux, Provincial Entomologist, Que. 



From the viewpoint of injurious insects, Ave have not experienced, during this 

 last summer, any higher damages than the previous year. It is to be noted that 

 most of those insects which are u'sually prevalent were rather scarce this year ; and 

 this especially proved true of two species, Hemerocampa leucostigma (Sm. and 

 Ah.) and Vanessa antiopa L. The few serious cases we have on record were 

 generally restricted to a limited area. On the whole, no regular outbreak has been 

 observed. 



Ornamental and Shade Trees. The most remarkable thing in this group 

 of plants was the large increase of poplar borers, Cryptorliynchus lapatlii Linn., 

 undoubtably due to the fact that shade tree plantations have made enormous pro- 

 gress these last two years. Plants imported from Ontario nurseries and elsewhere 

 are too often infested by this borer. The writer inspected a place where out of 

 eight Carolina poplars set up in May six were literally crowded with grubs and died 

 before the end of August. This situation has rapidly grown into a serious problem 

 requiring our attention without delay. 



The bronze birch borer, Agrilus anxiux Gory, has continued to kill our fine 

 cut-leaved birches at the same rate as last year ; in fact, we receive about the same 

 number of complaints each season indicating that the reproduction of the borer is 

 simply normal. From Levis and Portneuf counties injuries to the sugar maple 

 were reported caused by the cottony leaf scale, Phenacoccus acericola King. In 



