IMPERFECT SOCIETIES OF INSECTS. 295 
Asthelocust-eating thrush (Z'wrdus Gryllivorus) accompanies the locusts, 
so the lady-birds (Coccinella) seem to pursue the Aphides ; for I know no 
other reason to assign for the vast number that are sometimes, especially 
in the autumn, to be met with on the sea-coast, or the banks of large 
rivers. Many years ago, those of the Humber were so thickly strewed 
with the common lady-bird (C. Seplempunetata), that it was difficult to 
ayoid treading upon them. Some years afterwards I noticed a mixture of 
species, collected in vast numbers, on the sand-hills on the sea-shore, at 
the north-west extremity of Norfolk. My friend, the Rev. Peter Lathbury, 
made long since a similar observation at Orford, on the Suffolk coast; and 
about five or six years ago they covered the cliffs, as [have before remarked, 
of all the watering places on the Kentish and Sussex coasts, to the no 
small alarm of the superstitious, who thought them forerunners of some 
direful evil.1 These last probably emigrated with the Aphides from the 
hop grounds. Whether the latter and their devourers cross the sea has 
not been ascertained ; that the Coccinelle attempt it, is evident from their 
alighting upon ships at sea, as I have witnessed myself? This appears 
clearly to have been the case with another emigrating insect, the saw-fly 
(Athalia centifolia) of the turnip.’ It is the general opinion in Norfolk, 
Mr. Marshall informs us‘, that these insects come from over sea. A farmer 
declared he saw them arrive in clouds so as to darken the air ; the fisher- 
men asserted that they had repeatedly seen flights of them pass over their 
heads when they were at a distance from land ; and on the beach and cliffs 
they were in such quantities, that they might have been taken up by shovel- 
fuls. Three miles inland they were described as resembling swarms of bees. 
This was in August, 1782. Unentomological observers, such as farmers 
and fishermen, might easily mistake one kind of insect for another ; but 
supposing them correct, the swarms in question might perhaps have passed 
from Lincolnshire to Norfolk. Meinecken tells us, that he once saw in a 
village in Anhalt, on a clear day, about four in the afternoon, such a cloud 
of dragon-flies (Libellulina) as almost concealed the sun, and not a little 
alarmed the villagers, under the idea that they were locusts®; several 
instances are given by Résel of similar clouds of these insects having been 
seen in Silesia and other districts®; and Mr. Woolnough of Hollesley in 
Suffolk, a most attentive observer of nature, once witnessed such an army 
of the smaller dragon-flies (Agrion) flying inland from the sea as to cast a 
slight shadow over a field of four acres as they passed. A migration of 
dragon-flies was witnessed at Weimar in Germany in 1816, and one far 
more considerable, perhaps the greatest on record, May 30th and 31st 
1 Some such terrific idea would seem to have entered the sapient heads of the 
authorities of one of the principal towns of Berkshire, which in October, 1835, ac 
cording to the Reading Mercury, haying had ‘‘a most formidable invasion of this 
beautiful insect [lady-birds] .. . the parish engines, as well as private ones, were 
them? (li requisition, with tobacco-fumigated “water, to attack and disperse 
hem, I! 
*? Mr, Curis informs us that the aphidivorous flies (Sce@va Ribesii, Pyrastri, &c.), 
like the lady-birds, sometimes appear in myriads on the sea-coast, all flying in one 
RIGS and not even avoiding objects that lie in their course. (Brit. Ent, 
Ol, 509, 
5 Fn. Germ. Init. xlix. 18, 4 Philos. Trans, \xxiii, 217, 
5 Naturforsch. vi. 110 6 ii, 135. 
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