88 
weeds, and, as such, were decidedly beneficial, while others were indirectly 
of use, from the quantity of manure produced by their excreta and decaying 
bodies, which doubtless assisted to supyjly the wants of an exhausted soil. 
The larvae of twelve species of common butterflies fed upon weeds, and 
among them were mentioned the Swallow-tail, Papilio machaon, which fed 
on Umbelhferous plants, and the Frittaries, Melitaea cinxia and M. artemis, 
whose food were various varieties of plantains, fox-glove, &c., also the 
genera Cynthia and Vanessa, which were very destructive to thistles, nettles, 
and plants of a similar character. Twelve species also fed upon valuable 
plants, and as such were detrimental to the agriculturist and gardener. 
Means should be taken to destroy them, when birds, insectivorous quadru- 
peds, or insects of prey, did not sufficiently lessen their numbers, and the 
destruction of one female imago would prevent the deposition of a great 
number of eggs. The three species which, from their abundance, size, 
and frequent attacks upon the vegetables most cultivated in gardens, had 
been signalled out as the greatest enemies to horticulture, were Aporia 
crataegi, which was especially injurious to wall fruit trees, Pieris brassicae, 
and P. rapae, which committed great havoc amongst garden Cruciferae (as 
turnips, cabbages, &c.) and P. napi, destructive to the rape, horseradish, 
sea-kale, and other garden plants. The larvse which fed upon grasses 
were, as a rule, night-feeders, and it was therefore less easy to ascertain the 
comparative mischief done by various species ; probably the most important 
were Lasiomata Aegeria, and L. megara, feeding on wayside grasses, 
Hipparchia semele, and especially H. tithonus, H. janira, and H. hyperanthus, 
which fed upon meadow grasses, as well as Coenonympha pamphilus. 
Thecla quercus and T. rubi lived upon the leaves of the oak and bramble 
respectively. 
Of the British moths, 1900 species were known, and as they were mostly 
vegetable feeders, their numbers were very destructive. The primary 
division, the Sphinges, were of little economic importance, 20 out of the 
30 known species being rare. S. populi and S. ocellatus lived upon the 
leaves of the poplar, willow, and aspen. The larva of the Death's head 
Hawk Moth, Acherontia atropa,was sometimes sufficiently common to injure 
potatoes and jasmine. The larvae of the Privet and Elephant Hawk Moths 
were of little economic importance, and the Anthrocera were rather bene- 
ficial than otherwise. The class of Bombyces contained 104 species, many 
of great importance economically ; the genus Hepialus fed generally on the 
roots of plants, H. humuli doing much damage underground in hop- 
gardens. The larva of the Goat Moth, Cossus ligniperda, did an immense 
amount of injury to oak, poplar, and other trees, passing two years in the 
larval state, during which time it tunnelled through the sohd wood of the 
trunks ; it was, however, very difficult to destroy. The caterpillars of the 
Pygaera bucephala too, fed in colonies on many forest trees, frequently 
stripping them of their leaves. Dasychira pudibunda was the source of 
n;reat mischief in the hop-grounds, often seriously affecting the revenue 
