32 SECOND REPORT ON ECONOMIC BIOLOGY. 



case was any harm done, and here it occurred on the hawthorn hedge 

 as plentifully as on the pears. 



The insect is well-known to economic entomologists, and its 

 depredations have frequently been commented upon. 



LIFE-HISTORY. 



The moths appear towards the end of April or early in May. The 

 female deposits her eggs on the underside of the leaves. On hatch- 

 ing the tiny white larvae at once commence to make their way into the 

 leaf from the underside and feed upon the soft parenchymatous tissue 

 between the upper and lower epidermis. When full-fed the larva is 

 about a quarter of an inch in length, tinged with green and marked 

 with a darker green dorsal line. Anteriorly there are on each side of 

 the body four curious lateral processes. 



The larvae now leave the leaves, and towards the end of August 

 or early in September they spin white silky cocoons, drawn out to a 

 point at each end. The cocoons are attached to crevices on the trees, 

 to palings, etc., or may be found on the soil. In one of these situa- 

 tions they pupate, the pupa being pale brown in colour and somewhat 

 flattened. They remain in the pupa stage throughout the winter. 



PREVENTIVE AND REMEDIAL MEASURES. 



Where only a few trees are attacked, picking off the leaves and 

 burning same is recommended. 



Spraying with paraffin emulsion early in May proved beneficial, 

 and still more so that with caustic soda emulsion in the winter. 



WASPS. 



Throughout the whole of the country the plague of wasps during 

 1911 has been the subject of comment by all the agricultural and 

 horticultural papers. The injury they have done to fruit must have 

 been very great and the loss to growers considerable. 



In October, by letters, and through the medium of the Press, the 

 importance of waging a war of destruction upon these insects, has 

 been emphasised, particularly so the destruction of the nests and the 

 female insects at the end of the summer and in the spring. 



The subject is one in which the various Fruit Growers' Associa- 

 tions and Horticultural Societies might interest themselves, and accom- 

 plish a very useful and valuable piece of work. 



