so 



Habits of the Tomato Moth 



dropped from the gutter and fastened to a board running along the 

 ground, the flight of moths to the rest of the block being thus prevented. 

 The plants were not sprayed. 



The plants were examined at intervals of three or four days. When 

 they were small the examinations were made leaf by leaf, but when 

 this became impracticable it was made plant by plant, attention being 

 drawn to the presence of larvae by marks of recent feeding or by fresh 

 droppings. All found were removed. Eggs, and larvae up to a week 

 old, were counted as batches, and scattered larvae were counted indi- 



Week ending 



Diagram III. Showing the rise and fall in the numbers of larvae in the successive 



generations. 



vidually and classified into two groups: (1) as "young" larvae, up to 

 an age of about three weeks, and (2) as "old" larvae, which had passed 

 the fourth moult. The numbers collected weekly in the two collections 

 were plotted in a diagrammatic manner, the eggs being included with 

 the newly emerged larvae in the week following their collection. 



Diagram III thus shows the history of the pest over a period of 

 four months, the numbers of larvae being of course much reduced by 

 hand-picking. The dotted line represents the newly emerged larvae, the 

 broken line the young larvae, and the continuous line the ones which 



