The Biamond-bacli Moi/i. 
629 
■with the observation that they "preferred the barley " ; once that 
they were " occupied with early oats — no time to spare for cater- 
pillars " ; once the name only is mentioned, simply with the observa- 
tion that " spaiTOws are too numerous, and are against the swallows," 
and once that the reporter judged they were " of no use." The three 
other notes speak more favourably of their services. The observations 
name many kinds of large and small birds as noticed, and appear 
to point to assemblage of birds of the neighbourhood where great 
presence of caterpillars attracted them. 
Conclusion. 
The full teaching given in the foregoing reports can only be 
gained by careful working out of all the points of information, both 
as to coincidence and also in comparison one with another. 
In the summaries I have endeavoured to give some of the main 
points, but just looking at the matter generally, it appears to me 
(put very shortly) to stand as follows : — 
I think the evidence clearly points to the infestation having been 
■wind- borne to this country, because we have certain record of the 
appearance of great flocks of moths at various places on the eastern 
coast shortly before the caterpillars made their appearance, and 
where specimens of these moth appearances were submitted to 
entomologists they were found to be diamond-backs. Also, the 
observations show that there was no special amount of charlock (one 
of the chief field-weed plants on which the diamond-back caterpillars 
live), nor had weather been such as to prevent, either in previous 
autumn or before sowing the turnips, a careful cleaning, which would 
have got rid of food-plants of the pest. Further, it may be presumed 
that, if there had been the great number of caterpillars at work in the 
strip of country from Dover to Aberdeen which would have been 
requisite to produce our recent attack, something would have been 
noticed of them then, just in the same way as the presence and 
ravage have been noticed now. 
The little green caterpillars might easily have been overlooked, 
but every farmer would have been quick to observe what had 
happened to the leafage of the turnips. 
Also w^e have, I think, evidence that the attack came with a 
burst and gradually spread inland. This advance was found by Mr. 
Robson, at Hartlepool, to be at the rate of 1^ miles in two days. 
In that time from the appearance of the moths at Hartlepool, he 
found they had reached a locality where they were totally absent 
two days before. 
This appearance of the pests coincided in some cases certainly 
with dry weather, good for the infestation, and bad for the plants 
it attacked ; and that this weather was general may be presumed 
from the many reports, which after a while followed the first notice 
of ravage, that now rain had come attack and its consequences were 
lessening. 
Up to the past summer we have only had (so far as I am aware) 
