RAVAGES OF CATERPILLARS. 207 



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

 or Siberian crab (Pyrus prunifolia, 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 a leaf 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- 

 tersea and 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 ex- 

 periment.* This present spring (1830) they have 

 again appeared in millions 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,f 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 pro- 

 duces the prettiest moth of the genus ( Yponomeuta 

 Euonymellaj) but our preceding remarks all apply 

 to one species. 



In 1829 we remarked a very extraordinary num- 

 ber of webs of some similar caterpillar, of 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 



J. R. t Reaumur, Mem. ii, 198. 



