752 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



This method is frequently recommended as being effectual in 

 destroying the larvae. In my experiments they seemed not at all 

 affected by the application. 



A very thick dressing of lime was also applied to the surface of 

 the ground beneath the trees, with a view to destroying the larvae 

 when descending to pupate. Result as above. After the lime had 

 weathered down and formed a somewhat solid layer, the larvae bored 

 through it and pupated beneath. (See photograph, fig. 317 d.) 



(2) Hot water applied with a syringe at a temperature of 130 F. 

 This dislodged a few larvae, but did not kill them. 



(3) Paris green, obtained from a local chemist. Two applications. 

 Result nil. 



(4) " Paraffin or Kerosene Emulsion." 



Two applications were made of this — one hot, the other cold. 

 Result nil. 



N.B. — A Stott syringe was used to apply the insecticides. 



Fruit-tree Tortrix 

 (Penthina variegana, Hubner). 



In the Gardeners' Chronicle for June 1901, p. 342, I gave a descrip- 

 tion of this moth, accompanied by drawings illustrating its various 

 transformations. 



This insect has of recent years been very destructive to the Plum, 

 Apricot, Cherry, and Pear, occasionally attacking also the Rose. It 

 appears, however, to be much restricted in its distribution as a pest, but 

 I believe it occurs in most of our English counties. 



The following description of the insect in its various states is taken, 

 with due acknowledgment, from the Gardeners' Chronicle : — 



The caterpillars of this moth hatch from the eggs in the autumn, and 

 after feeding a short while they make for themselves little galleries or 

 cocoons on the bark of the tree (fig. 318, 6 x x x ). These cocoons are 

 chiefly composed of finely-spun silk, covered externally with tiny pieces 

 of foreign substances — portions of bud-scales, leaves, human hair, dirt, 

 &c., and sometimes the grubs bite off the outer layer of the bark or a 

 bud, and utilise it in the same way. So effectually are the galleries 

 concealed on the rough bark that it is almost impossible to find them, 

 and they are in no way conspicuous even on the smooth bark of a young 

 shoot. In these snug retreats the caterpillar passes the winter, finally 

 abandoning them in the spring, so soon as the flowers and young leaves 

 appear. Their habit, afterwards like that of many allied species, is to 

 live concealed between the leaves of the food-plant, which they effectually 

 fasten together by means of silken threads, and sometimes they will also 

 turn down a portion of the leaf, as shown at fig. 318, 5a. The cater- 

 pillars live in these retreats, and in them spin their cocoons, and towards 

 the end of May change to the chrysalis stage. 



Oddly enough, the caterpillar's retreat often consists of one living 

 and one dead leaf, and sometimes two or more individuals tenant the 

 same domicile. The young caterpillars feed chiefly upon the upper sur- 

 face of the leaves, leaving a network of veins (fig. 318, 5) in the same way 



