CHAELOCK-SEED WEEVIL. 85 



advanced to some size, and ou examination there was no reason to 

 doubt the Ceutorhynchiis beetles sent accompanying being of the species 

 contractus from their agreement with type specimens. 



This beetle is to some degree distinguishable from the two other 

 common kinds of weevil which may be found on Turnip and Mustard 

 (namely, the Ceutorhynchus sulcicollis, or " Gall Weevil," and the C. 

 assimilis, or " Seed Weevil ") by its smaller size, which is only about 

 half to three-quarters of a line in length. The general tint is shiny 

 black, the wing-cases sometimes having a greenish glance ; the fore 

 body is narrowed, and crossed by a deep groove in front, and strongly 

 punctured above. The proboscis is long and slender and arched. The 

 wings are ample, but so finely nerved, that with a magnifier of two- 

 inch power I was only able to distinguish the larger veins figured 

 at p. 83. 



The last season's observations have given a point of what may 

 prove of very practical interest, in the note of the contractus weevils 

 being found in great numbers as late as July 19tli on the growing 

 Mustard (not merely at the young sprouting plant). As yet, so far as 

 I am aware, we have no knowledge at all of where the early stages of 

 this weevil are passed, excepting that it has been reared from galls on 

 Charlock-roots. 



This, however, can hardly be the place from which such legions 

 come, which sometimes occur when weather is favourable for them and 

 bad for growth of the Turnip or Mustard crop. Those that appear in 

 April may very likely have hybernated ; but this can hardly be the 

 case with those that are found in June, still less those that were found 

 last season dropping in such quantities from the Mustard plants that 

 their fall could be heard as late in the season as the 19th of July. 



One way of gaining some advance in information would be dissect- 

 ing specimens from the time of the first observation onward, until we 

 found presence of eggs within the females. With sufficiently powerful 

 magnifiers this would give us a clue, and once found, the experiment 

 might be followed up by confining specimens with their food-plants 

 still growing, and watching for results. It would be worth some 

 trouble to make out the history of this (occasionally) very destructive 

 young Mustard and Turnip pest, and I should be glad to do what I 

 could in the matter. 



Last season's observations have somewhat helped by showing that 

 in wnfavourable circumstances, as where a crop is held back in growth 

 by frost, it may very likely be completely cleared by the weevil, whilst 

 the resowing on the same ground, but under more favourable circum- 

 stances for growth, will do well. 



We have also amongst notes sent in at various times an observation 

 of bad infestation of this C, contractus weevil occurring on ground 



