98 



Insect Pests. 



midwinter in box hedges in my garden. The first sign of larval life 

 may be noticed in JNIay. The female as a rule deposits one minute 

 egg on each apple leaf or sometimes cherry leaf In (at present) an 

 unknown period the larva hatches and bores into the leaf and there 

 forms a twisted and serpentine tunnel (Fig. 85) in the leaf, feeding 

 upon the soft parenchyma. Although I have been unable to note 

 the eo-g it is evidently laid upon, not in, the leaf, as a minute hole 

 can often be seen at one end of the tunnel through which the larva 

 has doubtless entered. The larva gradually enlarges this tunnel 

 as it grows ; at its end it is usually IJ mm. aeross. The tunnel 

 may be brown, black or grey, the larger end usually showing 

 a median line of dark " frass." Inside this tunnel will be found 

 the green caterpillar varying from pale to deep apple-green. It 

 reaches when full thrown 6 mm. in length ; the segments are 



\ Horace Knight. 

 FIG. 80.— APPLE LEAF MINER {LyonetUt clerckella). 



deeply constricted and more or less rounded ; the head is dark, 

 and there are two dark patches on the first segment and also a hair 

 on each segment. In general form the larva is flattened. The six 

 jointed-legs are brown and the eight prolegs also brown to almost 

 black. Larval life seems variable, for some were mature four weeks 

 after the first signs of the tunnels were noticed, others not until five 

 weeks. The larva can be seen in its tunnel by holding the leaf 

 against the light. They fit in so closely that they can scarcely move 

 towards the end of their growth. 



When mature they leave the leaf by eating their way out of the 

 gallery and crawl about upon the leaves for a short time. Usually 

 in a few hours they commence to spin a cocoon on the leaf These 

 cocoons are generally spun on the under side of the leaves but 

 may occur on the upper side, the latter only when they settle 



