[ 8 3 
the health of the public is not, nor cannot be affedled by them, 
either immediately or remotely. 
Some perfons have been alarmed lead:, as they have now in- 
creafed for three fucceffive years, they fhould be infinitely more 
numerous the next. It may afford feme fatisfafition to thole to 
be informed, that it is extremely probable, the trees and Ihrubs 
will not afford fufficient fuflenance to the prefent accumulated 
brood ; for fhould they be in the lead: dinted in their growth 
-at the time of their changing to Chryfalis, their wings will 
never expand, they will be incapable of flying, and of propa¬ 
gating their fpecies. It is alfo extremely improbable, that the 
ianle circumdrances fhould favour their increafe another year. 
What the actual caufes are which occafionally produce thefe 
extraordinary quantities of infedts will, perhaps, for ever re¬ 
main among the arcana of nature. We frequently hear that, 
in certain parts of the country, much damage has been fuffained 
by the Cock Chafer (Scarab teas MelolonthaJ ; in others, that the 
turnips have been deffroyed by a flnall Beetle, called the Fly- 
in others, that the fame plant has been con fumed by a Cater¬ 
pillar of a Tenthredo *; in others, that the wheat has been 
eaten in the ground by a fmall grub, producing an Rlater, or 
Spring Beetle -j~. One year the Aurelian fliall find plenty of 
painted Ladies fpapilio Cardui) ; another-year, with all his 
care, he fhall not find a Angle one. Lad: year the Sphinx Con¬ 
volvuli , Convolvulus Hawk Moth , and Papilio Hyale , clouded 
- For an account of which fee Alein, plate 62. Thefe, Mr. Frank- 
land informed me, were highly injurious laft year in fome parts of 
Yorkfhire. 
+ Mr. Lightfoot fhewed me.fome of thefe grubs; and related to me, 
that they were fo deftru£live this fpring about Uxbridge, that many farmery 
would be obliged to fow rrcfh grain. 
JYiloW 
