The Cabbage Root Maggot. 509 



ally, the slimy mass of soil and the then rotting roots combine to 

 give out one of the most sickening odors imaginable. 



The maggots work in a similar manner on radishes and turnips, 

 except that often their slimy burrows extend irregularly about in 

 the interior of the succulent root. Gardeners attribute much of 

 the toughness and stringiness of turnips and radishes to the work 

 of these maggots. 



In 1878 Dr. Riley found the maggots not " only working in 

 the normal way on the roots, but also burrowing in the stout 

 mid ribs of the leaves." Mr. Fletcher noticed a few of the mag- 

 gots working in a similar manner at Ottawa in 1890. 



Most writers, following Bouche, state that the maggot stage 

 lasts from three to four weeks. Mr. Whitehead of England says 

 from 24 to 28 days. We have no definite record on this point, 

 but our observations indicate that under favorable conditions 

 many of the maggots of this first brood attain maturity in less than 

 three weeks. 



The cabbage plants in our experiment plot on Long: Island were not set 

 until April i8 this year, but we bred a few flies as early as May 29 from 

 maggots taken from some of these plants; thus the egg, larval, and pupal 

 stages must have been passed in less than 41 days. Most of the maggots of 

 this first brood matured during the last week of May and the first few days of 

 June this year on Long Island. But maggots of various sizes occurred May 

 20. This was doubtless due to some of the flies appearing and ovipositing 

 later in the spring than others. 



Pupation. — When the maggots get full grown, they usually 

 work their way for an inch or two into the soil away from the 

 roots, and there enter the pupal stage. Sometimes this change 

 takes place in the galleries which the maggots have made in the 

 roots. The change from the maggot to the pupal stage is quite 

 gradual. The casual observer would notice but little difference 

 between a full grown maggot and a puparium which was only an 

 hour or two old ; they are of the same color, but the latter is a 

 little shorter, slightly more elliptical in shape, and shows a cer- 

 tain stiffness not seen in the maggot. These puparia can be easily 

 found if the soil arottnd the base of a badly infested plant be 

 closely examined, for a depth of two or three inches, at almost 

 any time from June 1 until the next April. 



