The Diamond-hack Moth. By George Bolam. 385 



observations in that direction ended, and I am not aware that the subject 

 has been tonched upon elsewhere. 



But while nature ever provides for holding in chock her own excesses, 

 the process is of necessity often a slow one, and man is certainly intended 

 to investigate and help himself in the matter. In the recently invented 

 " Strawsonizer," those who wish to try any of the insecticides or other 

 dressings have a most admirable implement at their command ; it disperses 

 the liquid in a fine spray over the leaves, in a manner which can scarcely 

 be excelled, and with a dry powder is almost equally efficacious. 

 Prevention, however, is always better than cure, and keeping the land in 

 good heart, and pushing on the growth of the young plants has always 

 been recognized as one of the best safeguards against loss from insect 

 attacks ; while with regard to the Diamond-back Moth a good deal may 

 probably be done by keeping down such weeds as form their natural 

 supplies, e.g. Runches and Wild Mustard. 



Diainond-hacked Moths and Ichneumon Flics. By 

 Andrew Amory, Alnwick, 



In common with most folks, I was very much interested with the 

 Diamond-backed Moth Plague, which wrought such havoc in the early 

 summer in turnip fields and gardens. 



The cauliflowers in my garden were completely riddled with the 

 caterpillars, (the moth I had never seen), so as soon as they began the pupa 

 stage, spinning themselves up on the under sides of the leaves they had 

 fed on, I took one of the cocoons and put it in a glass bottle. In about 

 two weeks the moth emerged. Wondering if some individuals had the 

 peculiar three diamond marks more clearly defined than those on the back 

 of this specimen, I imprisoned five more of the cocoons, which, to my 

 surprise, produced one Diamond-backed Moth, and four Ichneumon Flies 

 of a small species, corresponding with the size of the moth. 



The larva of the Ichneumon Fly is said to live upon the fatty portions 

 of a caterpillar, the egg being introduced by the parent, which is 

 furnished with an instrument to enable it to perform this hypodermic 

 operation. The ovipositer looks like a sting, only that it seems to be 

 always protruded, and besides its legitimate use, it serves as a weapon of 

 defence, as any one will be able to testify who has tried to capture the 

 common large Ichneumon with the naked hand. 



If my selection of five pupae was at all representative of what was going 

 on between the caterpillars and the Ichneumons, with the odds of four to 

 one in favour of the latter, here, then, was one of nature's checks to the 

 abnormal development of an insect pest, for not only were the caterpillars 

 prevented from ever becoming moths, but their very destruction was the 

 means of rearing a host of enemies to their species. 



