B.C. Entomological Society. 



far as we could tell from field observations and rearing hundreds of them 

 in the insectary, less than i per cent, of these eggs hatched before being 

 moulted ofif by the caterpillars. Another tachinid which deposits eggs on 

 the leaves of the food-plants is only active on hot, sunny days, and deposited 

 most of its eggs too late to be of value in the case of M. pluvialis. It was, 

 however, useful in the control of the erosa outbreak in the Uplands ; these 

 caterpillars being ten days to two weeks later, and the parasitism there ran 

 as high as 20 per cent. Two species of Hymenoptera were present in small 

 numbers — Campoplex (Ameloctonus) validus and a species of Rogas. 

 Both of these attack the very small caterpillars and are often useful para- 

 sites. Some other parasites were found attacking the pupae, but these were 

 also in negligible numbers. Overcrowding and diseases were very active 

 and important factors, and were successful in reducing the outbreak in all 

 parts of the city, with the exception of the Uplands, which was fairly free 

 from disease. 



To sum up, we see that, although the natural enemies of the tent- 

 caterpillars have been successful in reducing the outbreak in Victoria, it is 

 far from being under complete control, and it can increase so rapidly that 

 it will be necessary to assist nature in every way during the coming summer 

 in order to render these pests innocuous. In Vancouver much greater 

 efforts will be necessary. Last year recommendations were made to the 

 Councils of both cities with a view to assisting them in reducing the depre- 

 dations of the insects, but the results fell far short of being satisfactory 

 owing to a lack of any co-ordinated campaign. 



OBSERVATIONS ON THE USE OF POISON BAITS FOR 

 THE CONTROL OF CUTWORMS IN 1918. 



By M. H. Ruhm.'\n. 



For some years a mixture of Paris green or white arsenic and bran has 

 been advocated for use against cutworms. . The usual recommendation was 

 the application of the poisoned-bran bait round the base of young orchard 

 trees, or its distribution along the rows of plants, or its being placed in 

 small piles under shingles among the plants to be protected. In lectures on 

 control and in most publications emphasis is placed on the fact that the 

 Paris green or white arsenic is liable to cause injury to the plants or trees 

 if the bait is placed in contact with them. Evidence to this effect came to 

 the writer's notice in the spring of 1918 when called upon to investigate the 

 cause of the complete destruction of two separate plantings of 2,000 tomato- 

 plants and approximately 2 acres of beans. On examination it was imme- 

 diately evident that the plants had been burned by some poison applied to 

 prevent cutworm injury. On inquiry it was found that a bait had been 

 prepared consisting of 2 lb. of white arsenic to 50 lb. of bran mixed with 

 sufficient water to make a crumbly mass. The white arsenic was used 



