612 
TJie Diamond-hack Moth, 
the English and Scotch observations. The attack appeared neif 
the sea-coast, was most injurious to the weakest plants, and its effects 
were checked best by heavy rains. Probably Mr. Bloomer's simple 
plan of dashing water at the plants by means of a hose would be 
thoroughly serviceable. 
Appearance of moths in great numhers at various localities on 
the eastern coast about the end of June, and considerations jwintiyig 
to the probability of the infestations having been blown across the 
ocean from the Continent. 
On August 4 Mr. John E. Robson, of Hartlepool, Fellow of the 
Entomological Society, and Editor of the British Naturalist, de- 
scribed, in a letter sent by him to the Neiccastle Daily Journal (pub- 
lished on August 6), the enormous quantity of the Plutella crucifera- 
rum, or diamond-back moth, which had suddenly appeared at Hartle- 
pool on June 2-i, 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 possibiUty 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 Robson 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 J une 
24. On my return home my son gave me a specimen which he bad 
caught in the tennis court, and he described the numbers there as 
being beyond all he liad seen before. They were everywhere and 
in large numbers. At night I crossed the ' coal staitlis ' for a 
short cut, to where I wanted to collect ; they were there in 
thousands, — sitting on every coal waggon, on every bit of iron 
railway plate, on the wooden palings, and rising like a cloud at 
every step." 
Here JNIr. Robson gave me long details as to what kinds of plants 
grew in the neighbourhood (where there were any at all), and of 
amount of town land, showing that it was absolutely impossible that 
the moths should have been bred where they appeared. 
The moths, Mr. Robson observed, appeared on J une 24, and did 
not increase in numbers, but in unsuitable places, such as Hartlepool, 
they disappeared in two or three days, whilst further away a very 
small number remained on the coast edge, but they gradually spread 
inland. v 
In his published letter Mr. Robson shows something of rate of 
progress by mentioning that on the day of appearance at Hartlepool 
he found none at Hezleden Dene, about one and a half mile from 
the coast, and on June 2G they were swarmijig at this locality, having 
penetrated thus far in two days. 
Mr. Robson also brought forward the further considerations : 
"(1) For a long time previous to June 24 easterly winds prevailed, 
which would greatly assist the moths in crossing the sea. (2) The 
impossibility of so large a number of the insects passing through tlie 
larval stage without being observed by either farmers, gardeners, or 
