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VI. Some Obfervations on the Natural Hifory of the Curculio Lapathi 
and Silpha grifea. By Mr. William Curiis, Fellow of ihe Linnean 
Society. 
Read November 4, 1788. 
EVERAL fpecies of willow, particularly three of the mof 
ufeful and ornamental, the alba, the fragilis, and the babylonica, 
are well known to be fubjeét to the depredations of numerous 
infects, and of the larva of the Phalena Coffus in particular, who 
feed on the fubftance of the wood, and prove uncommonly deftruc- 
tive to the latter fpecies; for as the larvæ in each tree are generally 
numerous, in the courfe of a few years they deftroy fo much of the 
trunk, that the firft violent gale of wind blows down the tree. So 
infefted are the weeping willows in many nurferies with thefe in- 
feéts, that there is fcarcely one in ten to be feleéted free from them. 
The willows are infefted alfo in the fame way with the larvæ of the 
Cerambyx mofcbatuss and we have now the honour of laying before 
the Linnean Society fome account of the hiftory of a fpecies of 
Curculio, which was little fufpected of committing fimilar depreda- 
tions, but which in proportion to its fize is no lefs deftru&ive; 
as alfo fome obfervations on the hiftory of a fpecies of Siha, dif 
covered in inveftigating the economy of the Curculio. 
In the beginning of June 1780 I obferved a young tree of the 
Salix 
