PLANTING AND CARE OF TREES 173 



in groups of two, three or four, in the crevices of the bark or near 

 the buds. The larvae, hatching in a few days, begin to tunnel 

 in the twigs, and by the end of the season are about one inch in 

 length. They leave the small branches and crawl over the bark to 

 enter larger ones, cutting large galleries into them and expelling 

 the frass through round holes, which they soon close with silk wel^s. 

 During October the borers go deeper into the wood, and remain 

 through the winter two inches or more beneath the bark. They 

 pupate in their burrows the second spring, and before the moth 

 emerges the pupa works itself partly out of the opening, and the 

 aduJt flies away, leaving the empty case protruding from the 

 burrow. 



"There are few natural checks, only one parasite being known in 

 this country and four in Europe. It is believed, however, that 

 certain birds, especially w^oodpeckers, prevent the spread of the 

 leopard moth in the open country. Many larvae are doubtless 

 killed by the breaking off of the branches, which in cities are 

 carted away and destroyed. 



"Removing infested branches; injecting carbon disulphide 

 (bisulphide) into the burrows, and stopping the opening; probing 

 with hooked wire for the larva ; are some of the methods of control. 



"Planting species of trees not badly infested, like Oaks, Honey 

 Locusts and Sycamore, and especially those kinds that do not 

 grow very large, and have a smooth bark; placing trees further 

 apart, so that the larvae cannot easily crawl from one to the 

 other; and keeping the trees well nourished and vigorous, are the 

 chief preventive measures.'^ 



