282 Bionomics of Weevils 



LIFE-HISTORY. 

 Summary of Life-History in Britain as at present known. 



The most recent observations on the life-history of S. lineatus in 

 Britain occur, as far as I have been able to discover, in Miss Ormerod's 

 Reports from the year 1878 to 1892. They may be thus briefly sum- 

 marised. Weevils of S. lineatus issuing from their winter quarters were 

 known to attack peas and beans in spring. These beetles laid eggs, and 

 larvae of this species' were observed by Hart at the roots of peas in the 

 end of May. Weevils emerged from these during July. Sitones weevils 

 continued to be abundant on the peas until the time of harvesting, and 

 in autumn adult Sitones were to be found in abundance amongst clover 

 stubble. Sitones larvae were also to be found in great abundance at 

 the roots of clover from November to May and adults emerged from 

 these in June. As this observation is placed under the heading of Sitones 

 puncticollis some at least of the weevils reared from these larvae must 

 have been of this latter species. 



Miss Ormerod's conclusions from these observations are that the 

 weevils of lineatus after hibernation attack peas in spring, and produce 

 there another generation which emerges in July; that in June the weevils 

 developed from larvae which have spent the winter at the roots of 

 clover, join the swarms on peas, and at the time of harvesting the peas 

 all the weevils migrate to clover fields and a portion hibernate, but the 

 remainder lay eggs which give rise to larvae that feed on clover roots 

 throughout the winter. 



From this one would understand that there is a partial second genera- 

 tion of the pea-feeding weevils at the roots of clover, but whether this 

 generation is produced by the original hibernated weevils (in which case 

 it would not be in the true sense a second generation but only a later 

 brood of the same parents), or by their descendants, or by the weevils 

 that emerge from clover in June, is left in doubt. My researches show 

 that the life-history of two or more species have here been confused, as 

 the larvae which occur at the roots of clover in winter are not those of 

 S. lineatus but belong to other species, the life-history of which I intend 

 to deal with in subsequent parts of this paper. 



Summary of the Life-History as I have found it. 



In the beginning of the year, from January until March or April, 

 the adult weevils remain in their winter quarters, sheltering amongst 

 long grass, in stacks of pea straw, amongst the stubble of clover fields, 



