THE 
WEEKLY ENTOMOLOGIST. 
ENTOMA QUIDQUID AG-TJNT NOSTRX EST FARRAGO LIBELLI.” 
No. 10.] SATURDAY, OCTOBER 18, 1862. [Price 2d. 
EMIGRATION. 
k 
our last number we noticed the 
question of immigration of 
insects. This question has since 
suggested another, namely that of 
Emigration. We hare seen that a 
favorable wind and a peculiar state 
of atmosphere has caused the occur- 
rence of certain South European 
insects on our coast. There are, it is 
true, in this theory of immigration, 
difficulties, which we have alluded to 
in our former article. Still the mass 
of evidence seems to favour the idea 
that in some cases at any rate, the 
appearance of an.unusual visitant like 
j P. Bcetica, is owing to some such 
causes as those above mentioned. 
Especially does this view appear to 
have probability on its side, when aD 
insect has been traced in its steady 
course from south to north, as 
Bcetica has. May not the same 
causes operate in procuring the 
migration of insects from England, 
or, we should rather say, opposite 
causes ? Let it be granted that if we 
have a singularly warm summer in 
England, the Dover Cliffs, looking 
more than usually inviting, tempt 
the foreigner to our shores. Is it 
not, then, equally likely, that a- 
peculiarly ungenial summer will 
drive insects from our shores to seek 
a milder clime ? Perhaps one of 
our readers may be inclined to ask, 
will this theory serve any end ? will 
it explain any phamomenon? is it 
borne out by known facts ? We 
think it may go far to explain the 
temporary disappearance of many 
insects from places where they 
are occasionally or generally common. 
The following is a case in point 
Mr. Dale tells us this week that 
some of the Vannessidi are common 
in Dorsetshire this Autumn. Now 
we know they have been very scarce 
in the north, as, in fact, have Rho- 
palocera in general. Who can say 
but that they have been driven south- 
ward by the cold, wet weather which 
has been so prevalent in the north ? 
And it 1863 should be a wet year 
all over the country, for all we can 
tell, they may leave our island all- 
together, to return, we will hope, 
with the next warm summer. 
It would be interesting, as giving 
us additional information on this 
point, if any gentleman who has met 
with Northern species in more Sou- 
thern localities than usual, during 
this season and the last, would ac- 
quaint us with the fact. 
