RAVAGES OF CATERPILLARS. 213 



them in due bounds, the caterpillars of this moth alone, 

 leaving out of consideration the 2000 other British 

 species, would soon destroy more than half of our ve- 

 getation. 



The caterpillar just mentioned, amongst other pot- 

 herbs attacks coleworts and cabbage; and may some- 

 times be found there along with another, not uncom- 

 mon, but seldom very destructive, called by collectors 

 the burnished brass (Plusia chrysitis), which differs 

 little from the caterpillar of the y moth, except in be- 

 ing of a brighter green. Another, called the old gen- 

 tlewoman (Mamestra brassicce, TREITSCHE), is so 

 destructive to cabbages in Germany, that the gar- 

 deners gather whole baskets full and hnry them j 

 but as Rb'sel remarks, they might as well endeavour 

 to kill a crab by covering it with sea-water, for it 

 is natural to them to burrow under ground when 

 they change into chrysalides.* We have seen this 

 caterpillar, as well as that of the brown-eye (Mames- 

 tra oleracea\ do considerable damage in Wiltshire, 

 but nothing to what is reported of it in Germany. 



The leaves of cabbages, cauliflower, brocoli, cole- 

 worts, and turnips, are frequently devoured to a 

 more considerable extent by the sub-gregarious cater- 

 pillars of the white butterflies (Pontia brassicce, P. 

 napiy &c.) From the great multiplicity of the but- 

 terflies, indeed, and from there being two broods in 

 the year, we have reason to wonder that their 

 ravages are not more extensive. But we have re- 

 marked, that they seem more partial to wild than cul- 

 tivated plants ; for we have seen, near Islington, the 

 oleraceous weeds, such as rape (Brassica napus), 

 over-run with them in the very same fields with cul- 

 tivated cabbages, which were not touched ;| so that 

 the caterpillars are not always so injurious as we 

 might at first suppose, since in this case they tend to 



* Rosel, Inseckten, i, iv, 170. t J. R. 



