284 Bionomics of Weevils 



wooden sides about 1 foot high, and a frame above covered with muslin 

 or finely perforated zinc. These cages were made without bottoms and 

 the wooden sides were sunk in the earth, thus preventing any of the 

 larvae from escaping and providing the plants with abundance of air 

 and light. Admittance is obtained through sleeves let into the muslin, 

 or, when perforated zinc is used, by a movable lid. In the photograph 

 (Plate XIX) four of these cases are seen in position while the fifth is 

 awaiting the process of digging in. 



The hibernated weevils. The serious damage to peas and beans is 

 done by the hibernated weevils in spring. The date of their appearance 

 on these plants in spring varies according to the season and the latitude. 

 In Kent, in 1918, the spring was normal, and I noted the weevils on the 

 field peas for the first time on March 27th. In 1919 the season was very 

 backward and I found no weevils until April 8th, and the majority did 

 not appear till the middle of that month. In the north of Scotland, in 

 1919, the peas were not up till the beginning of May, and by the middle 

 of that month weevils were abundant on them. Early in spring when 

 the weather was cold the weevils were to be found in the daytime hiding 

 under lumps of earth near the base of the plant, and sometimes on the 

 stem of the plant near the root where it was sheltered by clods of earth, 

 but in warm, sunny weather many of the weevils were to be found 

 running about the leaves of the bean plants, or hiding in the leaf axils 

 or between the unopened leaves. I noticed that their method of attack 

 on the foliage of peas and beans differs after a certain stage. On beans 

 the weevils feed principally on the young unopened leaves of the terminal 

 shoots from the time the plant appears above ground till it is ready for 

 cutting. With peas the terminal growing shoots are only eaten whilst 

 the plant is small and not more than a few inches above the ground. 

 When over a foot high the growing shoots are rarely touched and only 

 the leaves near the ground are eaten. I attribute this difference to the 

 greater shelter which the stiff er bean leaves afford to the weevils whilst 

 eating. Large firm leaves, the axils of which form convenient hiding 

 places, surround the young shoots of the broad bean, whilst on peas the 

 young lea\es are slenderer, more exposed, and the weevils have to seek 

 shelter and a firmer foothold lower down. With both crops the most 

 serious damage is done by the weevils early in the spring while the 

 plants are still small. The weevils on disturbance immediately feign 

 death and fall from the plant, but after a short pause run quickly under 

 a clod of earth or down a crack, from which position they are not easy 

 to secure. When present on peas or beans under natural conditions I have 



