304 INSECTS. 



good service upon rose-trees, &c., being exceedingly 

 voracious. But the great adversary of the Aphis, and 

 one which, like itself, occasionally makes its appearance 

 in countless swarms, is the Ladybird. This, with its 

 larva, is so considerable a check upon the Aphis, that it 

 is wonderful that the hop planters have not learned to add 

 notices of the appearance of these insects to their reports 

 on the fly, as an indication of the help to be looked for 

 from them, either according to the time of year in the 

 present or the future season. 



The hop-growers, acting upon a principle all the 

 bearings of which they probably do not fully perceive, 

 check the production of the Aphides by a change of crop. 

 The success of this plan is owing to the fact of certain 

 species of Aphides feeding only on certain species of 

 plants, so that the children of the Aphis which flourishes 

 on the hop must starve upon the different plants which 

 take its place. Yet, even while acting upon the expe- 

 rience of this fact, it is difficult to convince the rustic 

 mind that it is a fact. The writer once came upon a 

 gardener intent on cutting down a fine sycamore because 

 it covered a neighbouring morella cherry-tree with 

 blight. In vain was the plea brought forward, "the 

 sycamore ' blight ' can't live on the cherry." " But there 

 is the cherry all covered with sycamore blight." It 

 might have been asked, " How do you known that the 

 sycamore is not covered with cherry blight ?" That 

 might very probably have been triumphantly answered 

 by, " Because the cherry-fly is black, and the sycamore- 

 fly green." But let philosophers say what they will, 

 it is not always as long from the lion's tail to his head 

 as it is from his head to his tail ; and, pleaded on the 

 other side, the argument had no weight 



