300 Wisconsin State Horticultural Society. 



young plants, or on the plants themselves. If a careful examina- 

 tion is given, it will soon appear for what purpose they are drawn 

 thither; small, oval, and white eggs will be seen on the stems 

 of the plants, or on the ground near at hand. These eggs soon 

 hatch out, and the little maggots make for the stem of the plant, 

 work their way down to the root, and burrow and feed upon it. 

 Sometimes they attack a plant in such numbers as to kill it; but if 

 it continues to develop, it is unfit for use. It is a serious pest to 

 market gardeners and those who raise quantities of radishes, using 

 the same land from year to year. They are much more numerous 

 and destructive on old ground than on new. Where once they 

 become established, they attack alike the radish, the early turnip 

 and early cabbage. Often in old gardens they will attack early 

 cabbage plants in such numbers as to destroy the entire crop, leav- 

 ing hardly a plant in large fields. It has been said that the worms 

 feeding on the radish, cabbage and turnip, are different; that each 

 is a different species; but the indications are that they are identi- 

 cal; what little difference, it is claimed, may be discovered in each, 

 can readily be accounted for in the effect of the food plant. It is 

 stated that the maggots found on the cabbage are larger than those 

 on the radish, and that the fly is larger and of a different shade; 

 but the form and the markings seem to be identical. Dr. Harris 

 describes the fly as " of an ash-color, with a silvery gray face, cop- 

 per colored eyes, and a brown spot on the front of the head; with 

 faint brown lines on the thorax and a longitudinal black line on 

 the abdomen, crossed by narrow lines." They are somewhat 

 smaller than the common horse fly, and of a lighter color, with a 

 metallic luster. When expanded, the wings are proportionately 

 longer, but when at rest they do not expand as much as those of 

 the house fly. There is quite a difference between the appearance 

 of the male and the female. The male has much larger eyes, occu- 

 pying most of the surface of the head and coming nearly together 

 on the crown; while in the female "they are widely apart, with a 

 broad black stripe between, which is shaded into a chestnut color 

 in front. The hind part of the body is more conical in the female 

 than the male." The male fly has more of a metallic luster, and 

 its body and legs are more thickly covered with bristles. They 

 often gather around the flowers, and at times may be seen in 

 crowds sporting in the air. The pupa is of a reddish brown color, 



