t 148 ] 



XXXVIII. On some vulgar Errors among Gardeners, re- 

 specting Insects being destroyed by cold. In a Letter to 

 the Right Honourable Sir Joseph Banks, Bart. By 

 William Spence, Esq. 



Read March 7, 1815. 



My dear Sir, 



u Vulgar errors" are prevalent in Horticulture as well as 

 in other arts, and one of these seems to me to be the notion 

 which we so often hear repeated, that caterpillars, grubs, 

 and slugs are destroyed by the cold of severe winters. As 

 a dependance on this supposed wholesale extermination of 

 the enemies of the gardener may often prevent his taking 

 active measures for their destruction, I shall make no apology 

 for begging to communicate, through you, to the Horticultural 

 Society, if you think them worthy of its attention, the obser- 

 vations which have induced me to believe, that this, like 

 many other received axioms, is unfounded. 



The facts mentioned by Reaumur and Lister relative 

 to the power of insects to bear cold uninjured, have long 

 led me to entertain this opinion. Not to advert to the well 

 known fact that the eggs of the silk-worm and of other 

 species, are capable of sustaining a degree of cold far greater 

 than any ever felt in this country, Reaumur found that a 

 common caterpillar (that of Phalcena Bombyx Chrysorrhcea,) 

 was not hurt by a cold of 19° below of his thermometer* 



* Memoires ponr servir a l'histoire des insectes, ii. p. 142. 



