326 Studies in Forestry [CHAP. xiv. 



of cockchafer grubs in nurseries ; whilst the collection of the 

 mature insects is practically confined only to beetles of the 

 larger kinds, like cockchafers and Spanish flies (Lytta vesica- 

 torta\ which may be shaken down from the crowns of poles or 

 young trees. Smaller species of beetles may also be caught by 

 means of decoy bundles of twigs or bark, which are burned 

 when infested ; whilst the large Pine weevil (Hylobius abietis] 

 is entrapped in narrow, upright-walled ditches, and then killed 

 by treading on them or pouring boiling water over them. 



B. Annihilation of Moths (Lepidoptera). 



True day-butterflies (Papilionidae] are practically innocuous 

 to woodlands. The various injurious species, Sphyngides, 

 Spinners, Spanners, Leaf-rollers, &c v are all moths or night- 

 butterflies. It is chiefly during the larval stage that successful 

 efforts can be made for the extermination of swarms of moths, 

 although something can also be done to reduce the number 

 of ova, pupae, and imagines. 



Sometimes the caterpillars may be collected merely by hand 

 (the workmen being provided with old gloves in the case 

 of hairy caterpillars like those of the Pine moth). This is the 

 case with those which hibernate under the moss, or which may 

 be brought down to the ground by shaking the poles or knock- 

 ing on the branches of trees with padded mallets or the flat 

 heads of axes, or which may be caught in isolating ditches. 

 By shaking and knocking, the caterpillars of the Pine Beauty 

 ( Trachea piniperda) and the Pine Span-worm (Fidonia piniaria] 

 may be brought to the ground for collection ; and the shaking 

 or tapping is most effective during cool weather, or early in 

 the morning, when their foothold on the foliage is looser than 

 during warm sunshine. In the case of the Spruce moth (Liparis 

 monacha] the newly developed larvae may easily be killed in 

 large numbers, whilst they are still clustered together in schools 

 of about ten to twelve, before wandering upwards to the crown 



