Dorothy J. Jackson 287 



28th May. By July 23rd some of the resultant larvae were lull grown and 

 all were mature by -luly 31st. The first pupa was found on July 30th, 

 and the remainder pupated between that date and August 6th. As the 

 eggs would commence hatching from 15th to the 18th June this would 

 give a larval period of from 45 to 49 days. 



It is interesting to note that even when the species is bred in captivity 

 under the most favourable conditions, only a few larvae survive from 

 the many eggs originally used in the experiment, though sufficient food 

 is present to support many more. As nearly all the eggs hatch when 

 observed in the laboratory, no doubt the greatest mortality occurs 

 amongst the newly hatched larvae (as pointed out by Baranov(i7)), 

 owing to lack of food whilst seeking for a root nodule to bore into. 

 Greater difficulty was also experienced in breeding larvae on clover than 

 on peas and beans. 



The pupal period. The full fed larva excavates an oval cell in the soil 

 for pupation | inch to 2 inches below the surface. In Kent I observed 

 the first pupa on June 10th, and in Ross-shire on July 24th. In the latter 

 locality pupae were abundant during August and still to be found in the 

 beginning of September, whilst on January 17th I succeeded in finding 

 two belated pupae in the soil of the old bean field. These must have 

 resulted from the last laid eggs of the old weevils as the following 

 breeding experiment testifies. On July 24th I placed some egg-laying 

 females from Ross-shire on to a sleeved pot of clover, and on November 

 19tb found a pupa in it which remained in this stage throughout the 

 winter. All these belated pupae died in captivity. The pupal stage 

 normally lasts from 16 to 19 days, but after casting the pupal skin the 

 weevil remains in the earthen cell five or six days until the cuticle 

 hardens and the normal colouring is assumed. About nine days before 

 emergence colour changes may be observed in the pupa. The eyes first 

 become brown, then the mouth parts and the apices of the femora and 

 the tibiae darken, and before emergence the wing cases, face, antennae 

 and legs are brownish grey. When the pupal skin is shed the weevil is 

 entirely pale ochreous, with the head brownish grey, the eyes black and 

 the apices of the femora and the entire tibiae deeper ochreous. The 

 following day the thorax and legs become brownish grey and the elytra 

 later turn greyish ochreous; by the fourth day the colour has become 

 gradually darker, and on the fifth day the normal colour is usually 

 assumed, though in some cases the cuticle is still soft. 



The newly <>>ii<>f<i<'<l weevils. These appear upon the peas and beans in 

 July in Kent, in August in Ross-shire. From Suffolk Mr B. S. Harwood 



19—2 



