242 



Insects most ijijurioiis tu Cultivators : — 



full grown ; at which time they have occasionally sufficient 

 strength to survive the injury, with the decay of a portion only 

 of their outer layer or root ; the centre part remaining sound. 

 In this manner whole beds are destroyed ; and it seems to be of 

 little use to sow again, as the fresh-sown plants fare no better. 

 In light soils especially, the attacks of this insect are occasion- 

 ally very annoying to the gardener. 



On stripping off the coats of the young onions which show 

 evident signs of decay, it is at once perceived that it is owing to 

 the attack of a small grub, destitute of legs, upon the vital parts 

 of the bulb or stem of the plant, that its destruction is occasioned. 



On pulling up a very 

 young onion {Ji'g.82. c), 

 its interior is found to 

 be completely devoured 

 by a single grub at 

 its very heart ; but, 

 in plants of larger 

 growth, I have counted 

 at least half a dozen of 

 these grubs, varying 

 considerably in size 

 iJ^S- 82. b). In the summer season, these grubs are about a fort- 

 night in arriving at their full growth. They generally consume 

 the entire of the interior of the onion; the outside skin of which 

 is alone left dry and entire, serving as a place in which they 

 undergo their transformations, without forming any cocoon. 

 i^S- 82. a.) In about another fortnight, the perfect fly makes 

 its appearance, the time varying, according to the season, from 

 ten to twenty days. 



The grub, or larva (j%. 83. : a, natural size; b, magnified), is 

 moderately long and cylindrical, but more conical towards the 

 head, which is of a variable form, furnished with two minute ten- 

 tacula. The body is fleshy, naked, shining, and of a white colour, 

 with twelve distinct segments. The breathing pores of the first 

 segment of the body are yellow, and the terminal segment is broad 



