330 IMPERFECT SOCIETIES OF INSECTS. 



cult to avoid treading upon them. Sonfie years afterwards 1 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 

 I 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.^ 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 Coccinellae 

 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 (^Aihalia centifoUce) 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 fishermen 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 shovels full. Three 

 miles inland they were described as resembling swarms of bees. This 

 was in August, 178*2. Unentomological observers, such as farmers and 

 fishermen, might easily mistake one kind of insect for another ; but sup- 

 posing 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 (Lihellulind) as almost concealed the sun, and not 

 a little alarmed the villagers, under the idea that they were locusts^ ; 

 several instances are given by Rosel of similar clouds of these insects 

 having been seen in Silesia and other districts^ ; and Mr. Woolnough 

 of HoUesley in Suffolk, a most attentive observer of nature, once wit- 

 nessed 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, 1839, when cloud-like swarms of these 

 insects (chiefly L. depressa) were seen at Weimar, Eisenach, Leipsig, 

 Halle, and Gottingen, and the intervening country, extending over a very 

 large district.''' Professor Walch states, that one night about eleven 

 o'clock, sitting in his study, his attention was attracted by what seemed 

 the pelting of hail against his window, which surprising him by its long 

 continuance, he opened the window, and found the noise was occasioned 

 by a flight of the froth frog-hopper (^Aphrophora spumaria), which 



' 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, according to the Read- 

 ing Mercury, having had "a most formidable invasion of this beautiful insect [lady-birds] 

 .... the parish engines, as well as private ones, were called into requisition, with tobacco- 

 fumigated water, to attack and disperse them." [ ! ! ! ] 



2 Mr. Curtis informs us that the aphidivorous flies { Scceva Eibesii, Pyrastri, &c.), like the 

 lady-birds, sometimes appear in myriads on the sea coast, all flying in one direction, and 

 not even avoiding objects that lie in their course. {Brit. Ent. fol. 51)9.) 



3 Fn. Gern. hit. xhx. 18. * Philos. Trans. Ixxiii. 217. 

 » Natur/ursch. vi. 110. « ii. 135. 



'' Weissenborn in Mag. Nat. Hist. N. S. iii. 516. 



