Reports to various Correspondents, 83 



the time. Now and then they leave the trees and wander about ; 

 some never return. It is probably some of these that are found in the 

 ground ; numbers of cases have been reported to me of these larvae 

 being found in the earth devouring and burrowing into the roots of 

 plants, such as dahUas. Normally in the spring of the third year 

 the larva (Fig. 13, h) comes to the entrance of the tunnel and close to 

 it forms a cocoon lined with silk and coated outside with wood chips. 

 The pupation takes place as a rule in May. The pupa (Fig. 13, rf) 

 is rich brown with rings of sharp spines on the abdominal segments. 

 The moth emerges in three or four weeks after pupation. Previous 

 to the emergence the pupa forces its way out of the cocoon and 

 partly out of the opening in the tree ; the empty pupal skins may 

 frequently be seen in that position. When kept under unnatural 

 conditions the caterpillars have taken four years to mature. 



Prevention and Remedies. 



Trees in close proximity to others that are attacked may be pro- 

 tected by thickly smearing the trunks over in May with a mixture 

 of clay and paraffin and soft soap. This should l)e made into a thick 

 paint and smeared all over the trunk up to eight feet and a thick 

 layer put around the base and the ground. Clay and cow-dung lias 

 l)een ibund to answer the purpose, but is not nearly as good as the 

 former mixture. This will prevent the eggs being deposited on the 

 trunk and roots where exposed. It is quite useless to scrub the bark 

 as suggested by Miss Ormerod, for the eggs are laid deep in crevices 

 and would not be reached in the majority of cases, neither can many 

 be rubbed off as suggested. For killing the caterpillars in the trees 

 the best plan is to place lunqjs of stick cyanitle in each hole and 

 smear the whole trunk over witli clay, the entrances to the holes 

 being firmly plugged up with the same. 



Paraffin emulsion squirted into the holes is said to be a good 

 remedy, but where tlie tunnels are very long and tortuous it is very 

 doubtful if many are killed b}- it. Sulphur and tobacco fumes blown 

 in by means of bee-l)ellows liavc also produced good results, but no 

 plan is as successful as the cyanide treatment and stopping up the 

 holes with clay. 



A correspondent writes that he has saved some valuable trees by 

 injecting about 2 c.c. of carbon bisulphide into the tunnel and 

 closing the hole with wet clay. This almost invarialjly killed the 

 caterpillars. 



All dead timber should be burnt in the winter or spring when 

 possible before the caterpillars escape. 



a 2 



