266 Lawson on Aphis Avence, 



bers that in autumn when many of the individuals have acquired 

 wings and left the bean fields, they spread over the country, dark- 

 ening the atmosphere with living clouds, — yet the farmers do not 

 find their bean crops very light, even during the worst seasons of 

 this so called " cholera fly." Items of information and assurances 

 such as the above served to allay the fears of the farmers, and to 

 prevent unnecessary expenditure of time and money and probable 

 injury to the crops in experimenting with the various remedial 

 applications recommended in the public prints to stay the *' insect 

 plague," such as smearing the standing grain with gum arabic, 

 pulverised hellebore, scotch snufF, flowers of sulphur, aloes and 

 other substances, which, however obnoxious, they might have 

 been to the aphis, would not have improved, by any means, the 

 flavour of the grain and flour. 



As the season advanced, the aphides increased in numbers, and 

 were no longer confined to wheat, but became abundant and con- 

 spicuous on oats and rye. Daily parcels of grain ears were being 

 received from various ports of the country from farmers who 

 feared that, while entomologists were ferreting out the history of 

 the insect, their crops would in the meantime be eaten up. In 

 the counties of Frontenac, Lennox and Addington, the insect was 

 universal. Wheat proved to be generally light; but the real 

 damage seems to have been done by a less conspicuous but more 

 destructive insect, — the wheat midge, — which was at work early 

 in the season, and, being a sly rogue in grain, was probably not 

 observed by many of the farmers, although quite common in the 

 Kingston district. 



As the season advanced, the insects preying upon the aphis 

 seemed to increase ; but the most marked eff'ect was observed to 

 result from the heavy rains of the night of Wednesday, 21st, and 

 Thursday, 22d August, which very sensibly reduced the numbers 

 of the aphis. Gardeners say that watering plants overhead rather 

 encourages the production of aphides than otherwise. No doubt 

 aphides like moisture, and especially a moist atmosphere. But it 

 was long ago observed by ray correspondent, Mr. Hardy, of Pen- 

 manshiel, who has devoted special attention to these insects, that 

 heavy rains served to dispel them. 



During the present season (1862) the aphis has again made its 

 appearance, and in as great numbers as before. It has naturally 

 attracted less notice, but appears to be widely difi'used in all the 

 cultivated parts of central Canada. In August, 1862, 1 traced it 



