TURNIP AND CABBAGE GNAT MIDGE. 131 



The weevil maggots are distinguishable by being (as figured at 

 p. 130, magnified) fleshy and legless, transversely wrinkled, yellowish 

 white in colour, with brown or pale brown heads, and when full-grown, 

 only about half an inch long. When full-grown, and consequently on 

 the premature opening of the seed-pods, they fall to the ground, and 

 bury themselves for their change to pupa or chrysalis (see figure, 

 p. 130). This is of a dull ochreous colour, with black eyes ; the pupal 

 state continues for about three or four weeks in the summer. 



The above notes are only given for convenience of comparison with 

 that of the Gnat Midge without the trouble of special reference ; some 

 detailed notes will be found on the attack, together with that of the 

 Turnip-flower Beetle, Melir/ethes (sneiis, in my Annual Keport for 1891, 

 accompanied by observations of some moderately successful methods 

 of prevention of damage, and in 1897 I again mentioned it, together 

 with the attacks of the Gnat Midge. 



On July 20th in the past season Mr. W. Sim, of Gourdas, Fyvie, 

 Aberdeenshire, N.B., who had communicated with me regarding pre- 

 sence of this Turnip-seed pest in the two preceding years, wrote me 

 again as follows: — "The larvae of the Turnip-seed Midge are again 

 very destructive with us. I will write you again " (W. S.). On 

 August 9th Mr. Sim continued : — " My crop of Yellow Turnip seed is 

 almost a complete loss. Last year the damage done was very extensive 

 and disappointing, so I had the roots planted last autumn in another 

 field. The strong healthy foliage and rich blossom in the spring 

 showed every indication of a full crop, but the seed-pods were scarcely 

 formed when they began to turn yellow by the attack of myriads of 

 the midge maggots. Now, when the crop is cut, the damage can be 

 ascertained, and I must be content with stones of small worthless 

 seed in place of hundredweights. The disease made its first appear- 

 ance on the 1st of July, and some of the larvae were full-fed and began 

 to escape three days afterwards. A few handfuls of the infested 

 seed-pods put in sterilized earth, and covered over began to give birth 

 to the midge about the middle of July, and by the end of the third 

 week they were issuing forth almost in clouds every time the covering 

 was removed. This destructive pest is likely to be overlooked, and 

 other causes attributed to the loss and failure of the crop, as only 

 those that are giving the subject their close attention could believe 

 and estimate the amount of damage. Swedes have seeded well, and, 

 though not absolutely clear of the midge maggot, are a good average 

 crop. The Turnip-seed Weevil has given little trouble this year." — 

 (W. S.) 



The larvae, or maggots, of the Gnat Midge (that is, of the Cecido- 

 viyia brassiccB of Winnertz, which these appear to be) are easily 

 distinguishable from those of the Seed Weevils by the heads being so 



