577 



to the spruce or balsam budwomi [Tortrix fmniferana, Clem.] in the 

 recent outbreak [see preceding paper] was about 10,900,000,000 

 merchantable cu. ft. of balsam and 1,087,000,000 cu. ft. of spruce. 

 The total forest area of Quebec and Ontario is many times larger than 

 this, large portions of it being virgin territory for which these figures 

 would be too small. As a factor in experimental investigation, the 

 value of sample plots, where the numbering of trees makes their 

 annual location easy, is pointed out, as it is only when all facts of the 

 life-history and habits of an insect pest are thoroughly known that 

 successful remedial measures can be planned. 



LocHHE AD (W.) & Tawse (W. J.). Experiments on the Control of the 

 Onion Maggot, 1921. — 14th Ann. Rept. Quebec Soc. Prot. Plants 

 1921-22, Quebec, 1922, pp. 43-48, 3 figs. 



In these experiments for the control of the onion maggot [Hylemyia 

 antiqua] I oz. sodium arsenite was dissolved in 1 gal. boiling water, 

 with the addition of 1 pint cheap molasses, and was applied both 

 in shallow pans placed at regular intervals through the field, into 

 which onions were placed and the mixture poured over them, and also 

 as a spray. About 20 pans were used per acre, each being 1| in. 

 deep and 6 in. wide, and they were refilled every week for four weeks. 

 This method is based on the fact that the flies do not oviposit until 

 about ten days after emergence, and that they are attracted to sweet 

 substances. There are probably three generations in a year, adults 

 first appearing about mid-May. The larvae, after feeding on the 

 bulbs, pupate in the soil, where they pass the winter. The open pans 

 were found to give very good results, were easy to refill and did not 

 hinder cultivation. The spray was less successful, required more 

 material and was more difficult to apply. 



Keen AN (W. N.). The Distribution of the European Com Borer in 

 Canada and the United States. — 14th Ann. Rept. Quebec Soc. 

 Prot. Plants 1921-22, Quebec, 1922, pp. 48-52, 1 map. 



The gradual spread and present distribution of the European corn 

 borer [Pyrausta nubilalis, Hb.] in the United States and Canada is 

 outlined, and the present infested area is shown on a map. 



Maheux (G.). Som.e Insects Injurious to Shade Trees in Quebec. — 



14th Ann. Rept. Quebec Soc. Prot. Plants 1921-22, Quebec, 1922, 

 pp. 62-67. 



Leaf-eating insects that have caused much defoliation to shade 

 trees about the city of Quebec in recent years include the tent cater- 

 pillars, Malacosoma americana and M. disstria, which have done a 

 great deal of damage to maples. Feeding on the leaves begins in early 

 June and continues until about the 20th, when the trees are partly 

 or wholly defoliated. In early July the moths fly in great numbers 

 about the Hghts in the streets. The winter is passed in the egg stage. 

 Vanessa antiopa (elm caterpiUar) begins feeding on the leaves of elm 

 in late July and extracts all the chlorophyll from the leaves, leaving 

 them yellow and transparent. The larvae feed for about four weeks, 

 and after pupation adults appear from about 20th August to 15th 

 September ; after hibernating they deposit eggs during the early 

 spring days on the small branches of elm, willow and poplar. Hemero- 

 campa leucostigma (white-marked tussock caterpillar) defoliates poplars, 



