INSECT PESTS 81 



buds and leaves, and when full fed change into brown 

 chrysalides in the nests, from which in due course the 

 moths emerge. The damage is serious, since it prevents 

 the rod from attaining its full length and also, owing 

 to the destruction of the growing point, encourages 

 the production of lateral shoots, a condition known as 

 " bushy top." So far as the Somerset district is 

 concerned the most common species are Hypermcecia 

 cruciana and Depressaria conterminella. 



(2) There are two species of willow clearwing moth, 

 of which the first, Trochilium bembeciforme, the Willow 

 Hornet Clearwing, so closely resembles a large wasp or 

 hornet that it may readily be passed over. The second 

 species, the Red Tipped Clearwing (Sesia fomiccejorme} 

 also has little resemblance to a moth, and is perhaps 

 more like an ichneumon fly. The larvae of these moths 

 are white, grub-like caterpillars with brown heads and 

 eight pairs of legs, which are small but evident. The 

 Hornet Clearwing larva lives inside the stumps and 

 especially in rods of two years' growth or more. The 

 larva of the Red Tipped Clearwing lives mainly on the 

 stumps. The larvae of both species pupate in the 

 spring in the burrows, and the moths emerge in June 

 and July. The damage done by these insects is not 

 very evident unless a few stumps are cut open, when it 

 is often found that the wood is tunnelled in all direc- 

 tions by the larvae, \vhich at first reduce the produc- 

 tiveness of the stump and later kill it altogether. 

 These two species and the Willow Weevil (Cryptor- 

 rhynchits lapathi] are the insects chiefly responsible 

 for the decay of stumps. 



Willow Gall Midges. These insects in the adult 

 stage are minute midges or flies. The most injurious 

 species lay egg's in the terminal buds of the rods, which 



