THE CA.NADIAN ENTOMOLOGIST. 



365 



POPULAR AND PRACTICAL ENTOMOLOGY.— No. i8. 

 The Bean Weevil {Briichus obtectus^ Say). 



BY ARTHUR GIBSON, ASSISTANT ENTOMOLOGIST, CENTRAL EXPERIMENTAL 



FARM, OTTAWA. 



An insect which, fortunately, has only been reported on a few 

 occasions as doing damage in Canada, is the Bean Weevil, Bruchus 

 obtectus^ Say. Authentic instances of injury by this insect have been 

 received from one locality in Ontario, and from two in Quebec. The 

 injury in all cases was to seed beans. 



The Bean Weevil (Fig. 48) is a small, hard-shelled beetle, one-tenth 



of an inch long, oval in form, with the head 

 bent down and more or less concealed, as seen 

 from above, and prolonged into a squarely-cut 

 snout, or beak. Its antennte are distinctly 

 jointed and enlarged at the tip, the first four 

 joints and the last one reddish. The wing- 

 covers are marked with ten impressed and 

 dotted longitudinal lines, and the whole body 

 is covered with short, silky hairs. The lines on 

 the wing-covers are broken up into pale 

 yellowish dashes and dark brown spots. The tip of the abdomen extends 

 beyond the wing-covers, and is of the same reddish tinge as the tips of 

 the antennae and the legs, but is covered more or less with short, silky 

 hairs, and bears a central white line, but there is no appearance of the 

 two black spots so conspicuous in the Pea Weevil, which it resembles in 

 shape and movements. Compared more closely with this latter wdl- 

 known insect, the Bean Weevil is not one-half so large, is more soberly 

 coloured, having less white on the wing-covers, and lacks the white spot 

 on the middle of the hinder part of the thorax, and the two oval black 

 spots mentioned above, which are present on the exposed tip of the 

 abdomen of the Pea Weevil. 



" The life-history of the Bean Weevil differs in some important 

 points from that of the Pea Weevil. The eggs of both are laid u[)on the 

 pods while these are young and tender. On hatching, the young grub of 

 the Bean Weevil eats its way inside and penetrates one of the forming 

 beans, several grubs entering a single bean, each one forming for itself a 

 distinct cell. They become fuU-grovvn, and change to pup?e in the 

 autumn, and a little later to the perfect beetles. The date of emergence 



November, 1906 



Fig. 48. 



