750 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



result that the leaf turns brown and in time falls from the tree. The first 

 brood of grubs are full fed about the middle of June. They descend to the 

 ground, spin their cocoons, and therein turn to pupae. In August I have 

 found the insects in all stages, viz. : eggs, larv?e in all stages, pupae, and 

 perfect insects. There are, therefore, at least two broods in a year, and in 

 all probability more, and, as in the Gooseberry saw-fly, there appears to be a 

 good deal of overlapping of the broods during the latter part of the summer. 

 The cocoon (figs. 316, 317) is about one quarter of an inch long ; it is formed 

 by cementing together the surrounding grains of sand or earth, and is 

 therefore of precisely the same colour as the surrounding earth, which 

 renders it very obscure and difficult to find when in comparatively small 

 numbers. The exact spots where the grubs pupate, or rather spin their 

 cocoons, are all along the wall, about one inch below the surface, and also 

 upon the roots of the trees where the bark is roughest. In the latter 



I 



( Fig. 316. — Cocooxs of Slugworm on Roots of Pear. (Natural size. Original.) 



position (fig. 316) they are extremely hard to find, but they are much more 

 easily detected when adhering to the wall. In the latter position I have 

 found them clustered together, forming a mass nearly one inch thick 

 (fig. 317 A-c) and extending along the entire length of the wall on which 

 the trees were trained ; and where the cocoons were thickest they 

 averaged 500 to the lineal foot. Thus under one tree covering a space of 

 20 feet, some 10,000 cocoons were found. Although of a very brittle 

 nature, the cocoons were very firmly attached to the wall, and when 

 removed many of them brought away fragments of brick and mortar 

 with them. I should also add that the larvae in many instances had 

 burrowed into the mortar between the bricks, forming their cocoons with 

 the dislodged materials (fig. 317 a). 



Treatment : — 



(1) Remove all surface soil to a depth of four inches, and to a 



