Insects Injurious to the Apple. 49 



The larva is yellowish-white ; on each segment are small black 

 processes, from each of which springs a short black bristle. The 

 head is brown, with two black spots, and is retracted into the 

 first segment, which is shining black and broad. The larvae work 

 right into the wood, and eat away the hardest parts, forming tunnels 

 of some length. When full grown, which is in about ten months 

 after their advent from the egg, they reach as much as 2 inches in 

 length, but shorten very much prior to casting their skin for the 

 pupal change. Each larva spins a silken cocoon, mixed with particles 

 of wood, beneath the bark, in which it changes to a bright brown 

 pupa, 



REMEDIES. 



When only a few of the larvse are present, it is possible to get 

 rid of them by suffocating them by various vapours. An ordinary 

 pair of " bee bellows " filled with touchwood and sulphur alight will 

 blow or force the fumes into the hole. The fumes ascend and reach 

 the larvre even if they are some distance up the trunk. Bisulphide 

 of carbon fumes I found also successful in destroying the caterpillars. 

 In all cases it is most essential to plug up the entrance hole with 

 wax or wood so as to stop further insect attack and wet from entering, 

 which soon leads to the rapid decay of the tree. But frequently we 

 are unable to detect any hole ; all that is seen is that the branch of 

 the cherry, pear, plum or apple tree is dying. It is then best to cut 

 the branch right back until sound wood is reached, and slit up the 

 branch until the larva is found, and then kill it to prevent further 

 damage. 



REFERENCES. 



(1) Kollar, Vincent. ' Insects Injurious to Gardeners, Foresters and Farmers/ 



(Eng. Trans., 1840.) 



(2) Lintner, A. J. 'Ninth Eeport on Injurious Insects of the State of New 



York,' p. 426 (1893). 



(3) Theobald, F. V. Eeport upon Insect Pests in 1894, with especial reference 



to Insects attacking the Walnut (1895). 



(4) Theobald, F. V. 'The Animal Pests of Forest Trees,' p. 27 (1904), and 



Journal S. E. Agri. Coll., No. 13, p. 180 (1904). 



(5) Ormerod, E. A. ' Handbook of the Insects Injurious to Orchard and Bush 



Fruits' (1898). 



(6) Whitehcad, Sir C. ' Eeport on Insects Injurious to Fruit Crops,' p. 44 



(1886). Agricultural Department. Privy Council Office. 



