RAVAGES OF CATERPILLARS. 207 



usual favourites. Thus, in 1825, the cherry-apple, 

 or Siberian crab (Pi/rus pninifolia, Willdenow^), 

 so commonly grown in the suburbs of London, 

 swarmed with them. On a single tree at Islington 

 we counted above twenty nests, each of which would 

 contain from fifty to a hundred caterpillars ; and 

 though these do not grow thicker than a crow-quill, 

 so many of them scarcely left aleaf undevoured, and, 

 of course, the fruit, which showed abundantly in 

 spring, never came to maturity. The summer fol- 

 lowing they were still more abundant on the haw- 

 thorn hedges, particularly near the Thames, by Bat 

 terseaand Richmond. Since then we have only seen 

 them sparingly ; and last summer we could only find 

 the single nest upon which we tried the preceding 

 .xperiment*. This present spring (1830) they have 

 again appeared in miilions on the hedges. 



Reaumur says that in some years they were ex- 

 ceedingly destructive to his apple-trees, though they 

 did not touch his pears, plums, or apricots t, which 

 agrees precisely with our own remarks. We are well 

 aware that there are several species of the small er- 

 mines, all similar in manners, such as the one which 

 feeds on the spindle-tree {Euonymus), and produces 

 the prettiest moth of the genus {Yponomeuta Euony- 

 mella) ; but our preceding remarks all apply to one 

 species. 



In 1829 we remarked a very extraordinary num- 

 ber of webs of some similar caterpillar, oi which we 

 did not ascertain the species, on the willows in Hol- 

 land and the Netherlands, from Amsterdam to 

 Ostend. In some districts, particularly near Bruges 

 and Rotterdam, the leaves were literally stripped 

 from whole rows of trees ; while other rows, at no 

 considerable distance, were entirely free from their 

 ravages. A foreign naturalist, quoted by Harris in 

 * '. R. t Reaumur, Mem. ii. 198. 



