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 larvae 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. — rThe 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 



" Natiirforsch. xvii. 226. 



