8 IMPERFECT SOCIETIES OF INSECTS. 
emigrate in files, like the caterpillar of the procession- 
moth. First goes one, next follow two, then three, &c., 
so as to exhibit a serpentine appearance, probably from 
their simultaneous undulating motion and the continuity 
of the files; whence the common people in Germany 
call them (or rather the file when on march) heerwurm, 
and view them with great dread, regarding them as 
ominous of war. These larvee are apodes, white, sub- 
transparent, with black heads*.—But of insect emigrants 
none are more celebrated than the locusts, which, when 
arrived at their perfect state, assemble as before related, 
in such numbers, as in their flight to intercept the sun- 
beams, and to darken whole countries; passing from 
one region to another, and laying waste kingdom after 
kingdom :—but upon these I have already said much, 
and shall have occasion again to enlarge.—The same 
tendency to shift their quarters has been observed in our 
little indigenous devourers, the Aphides. Mr. White - 
tells us, that about three o’clock in the afternoon of the 
first of August 1785, the people of the village of Selborne 
were surprised by a shower of Aphides or smother-flies, 
which fell in those parts. Those that walked in the 
street at that juncture found themselves covered with 
these insects, which settled also upon the hedges and in 
the gardens, blackening all the vegetables where they 
alighted. His annuals were discoloured by them, and 
the stalks of a bed of onions quite coated over for six 
days after. ‘These armies, he observes, were then, no 
doubt, in a state of emigration, and shifting their quar- 
ters; and might have come from the great hop-planta- 
tions of Kent or Sussex, the wind being all that day in 
* Naturforsch. xvi. 226. 
