CATERPILLARS. 



381 



An allied species of saw-fly {Nematus Caprece, STP]pnEXs) 

 frequently becomes extensively destructive to several 

 species of willow, sallow, and osier. It is so like that of 

 the gooseberry and that of the willow (^Nematus sdlicis)^ 

 which is not British, that it has been confounded with 

 these by Fabricius, Stewart, Gmelin, and other authors. 

 In the summer of 1828, we observed a considerable group 

 of young standards of the golden osier (^Salix vitellina), in 

 a nursery at Lewisham, rendered quite leafless by these 

 caterpillars; which, when feeding, throw themselves into 

 singular postures by holding only with their fore feet. The 



Nematus caprem, on the osier; 6, Sdandria alni? on the alder. 



fly appears in spring, and places its eggs in a round patch 

 on the back of the leaf, and not along the nervures, like the 

 gooseberry saw-fly. During the three last summers, we 

 also remarked that the alders (^Alnus glutinosa) along the 



