2OO ENTOMOLOGICAL NEWS. [June, '09 



studies by potting healthy specimens. To prevent accidental 

 injury and to keep away parasites, which may enter through 

 the open doors and windows, the plants can be covered with 

 Welsbach chimneys, whose upper end is closed with Swiss 

 netting. Yet even with the greatest care an experiment in 

 individual breeding occasionally fails through the mysterious 

 disappearance of the insect. This is undoubtedly because the 

 aphid becomes restless, if the supply of food is not perfectly 

 satisfying, and wanders down and is lost in the apparatus. 

 Therefore, if the observer notes that a certain number of 

 young larvae are with the adult, he knows that she produced 

 this number since the last record was made, but he cannot 

 know how many more were born that wandered away and 

 were lost. Consequently, if absolutely reliable data are to be 

 secured, each insect must be confined so that, if it dies, it 

 can be easily found. For this purpose I have used success- 

 fully glass tubing of a large diameter. The portion of the 

 potted host carrying the insect is placed in the tube, which is 

 securely held in place by attaching it to a stick thrust in the 

 soil. The upper end is closed with fine netting, and the lower 

 end is plugged with cotton, to prevent the escape of the in- 

 sect along the plant stem. If black cotton is used, any light- 

 colored plant louse or exuvium that falls on it will be easily 

 seen. By using succulent, healthy plants and reasonable care, 

 reliable results can thus be obtained. If the apparatus is kept 

 in diffuse daylight and not too much plant tissue is placed 

 in the tube, moisture and fungi will not be especially trouble- 

 some. Mr. J. J. Davis has secured the individual life history 

 of Aphis maidi-radicis by using large glass vials as vivaria 

 in which the plant is kept growing with a ball of moist cot- 

 ton at the bottom. (U. S. Dept. Agric., Bur. Ent, Tech. Sen, 

 No. 12, Pt. VIII, p. 124-5.) 



I believe that by giving careful attention to the proper 

 methods the Aphididae can be studied as advantageously as 

 any other group of insects. I wish to acknowledge Professor 

 Wheeler's kind criticism in the preparation of this article. 



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