450 FARMERS' INSTITUTES. 



in hue, some of them were hardly distinguishable from flies reared from 

 maggots infesting the cabbages. One maggot was found working in the 

 the succulent growth of a raspberry cane, which was also precisely like the 

 onion and cabbage maggots. The fly reared from this maggot was the typical 

 cabbage Anthomyia. 



Thus it will be seen that we have three excellent reasons for the opinion 

 that all these Anthomyia are varieties of one single species. First, the fact 

 that they intergrade perfectly; secondly, they can be removed from one plant 

 to another, as from radish to cabbage, and thrive as well; thirdly, the fact 

 that though none could be found in 1885 on onions, yet in 1886 an entire 

 onion bed waa thoroughly devastated. If these were cabbage flies, which in 

 the absence of cabbage plants attacked the onion as a second and necessary 

 choice, then we easily understand and can explain this curious wholsale 

 onslaught. 



It will occur at once to all that this is a matter of great practical moment. 

 If these flies are varieties of one species, and though preferring radishes or 

 cabbages, will in the absence of these plants attack onions, it is of great 

 importance that the gardener should know it. 



• REMEDIES. 



After several years of close experimentation, I am of the opinion decidedly, 

 that the only practicable remedy in the hands of the practical man against 

 these Anthomyia, is change of place of the plants, or covering the plants so as 

 to exclude the flies. It is true, that I have killed these maggots both in the 

 garden and on potted plants in the laboratory, by use of the kerosene and 

 soap mixture, and also by the use of bi-sulphide of carbon. Yet upon a 

 thorough trial I am persuaded that these remedies cannot be made prac- 

 ticable. Difference in soils, seclusion of the maggots, which bore quickly 

 out of the reach even of these insecticides, make their use uncertain, and 

 them unsatisfactory insecticides in this warfare. 



As suggested above, we have been entirely successful now for two years, by 

 removing the cabbages ninety rods from where any of these susceptible plants 

 had been previously raised or grown. True, an orchard intervenes, and 

 other susceptible plants remained in the old position. But we are certainly 

 warranted in the opinion that by making the distance of the removal great 

 enough, we should escape this evil. Some plants might be planted in the 

 old places as lure patches, which could be pulled and destroyed before the 

 maggots were fully grown ; though this would not be desirable, in case the 

 circumstances permitted a sufficient removal. If we can starve the pest, it 

 would be very wise and desiaable. Of course it is possible that other plants 

 would be selected in case of the entire removal of those named. 



We could also secure early radishes by growing them in cold frames under 

 musquito netting, or thin factory or cheese cloth, and thus certainly fence 

 out these flies. This method is surely practicable and inexpensive, though 

 it would require some care. 



We are also experimenting with paper collars resting upon the ground and 

 closely encircling the plants. In some cases we used adhesive paper, such as' 

 is sold in the drug stores to trap flies. We thus hope to secure the eggs, and 

 keep them from hatching. The number of eggs we have secured from a 

 single plant is astonishing. They were numbered by hundreds. We have 



