DIAMOND -BACK MOTH. 



155 



The above notes, it will be seen, coincide with the main points of 

 the English and Scotch observations. The attack appeared near the 

 sea-coast, was most injurious to the -weakest jilants, and its effects 

 were best checked by heavy rains. Probably Mr. Bloomer's simple 

 plan of dashing water at the plants by means of a hose would be 

 thoroughly serviceable. 



I had also a communication sent me by Mr. Champion Eussell 

 (of Stubbers, Eomford, Essex) whilst at Brockley Park, Stradbally, 

 Queen's Co., Ireland, in which he mentioned that there had been some 

 Turnip caterpillar attack, probably Diamond-back ; but that the 

 Swedes in which they were appeared to have out-grown the attack. 

 At the date of observation (August 30th), Mr. Champion Eussell men- 

 tioned that most of the moths had developed and taken wing, and 

 there were many empty cases. A few cocoons were sent to me, which 

 enabled me to identify the attack with certainty from the moth, as being 

 that of Diamond-back. The above note records the most westerly 

 locality of observation of which report was sent me. 



Appearance of moths in great numhers at varlons localities on the 

 eastern coast about the end of June, and considerations p>ointin(j to the 

 probability of the infestations having been blown across the ocean from the 

 Continent. 



On August 4tli Mr. John E. Eobson, of Hartlepool, Fellow of the 

 Entomological Society, and Editor of the ' British Naturalist,' de- 

 scribed, in a letter sent by him to the ' Newcastle Daily Journal ' 

 (published on August 6th), the enormous quantity of the Plutella cru- 

 ciferaruw, or Diamond-back Moth, which had suddenly appeared at 

 Hartlepool on June 24th, together with some other points which, 

 coming from a skilled entomologist, used to identify species and 

 observe habits, were very valuable, as they proved almost beyond 

 possibility of doubt that these vast numbers of moths were not 

 developed on land, but had been wind-borne from the continent of 

 Europe. 



On application to Mr. John Eobson he was good enough to write 

 me more in detail as follows : " As stated in the letter, I was collecting 

 at a little distance from the coast on the evening of June 24th. On 

 my return home my son gave me a specimen which he had caught in 

 the tennis court, and he described the numbers there as being beyond 

 all he had seen before. They were everywhere and in large numbers. 

 At night I crossed the 'coal staiths' for a short cut, to where I wanted 

 to collect ; they were there in thousands, — sitting on every coal wag- 

 gon, on every bit of iron railway plate, on the wooden palings, and 

 rising like a cloud at every step." 



