EXPERIMENTS IN CONTROL. 9 



dorsally near insertion of antennae. Eyes prominent and considerably polished. 

 Legs reaching to tip of wing-cases; antenntw shorter. Median line of prothorax quite 

 sharp and carinate, median line of mesothorax faintly elevated, somewhat polished. 

 The whole anterior portion of body finely and closely granulated. i^Ietathorax and 

 the three following abdominal segments, with numerous shallow, circular depressions, 

 each haAdng a central granule. The circular depressions on abdominal joints 4-8 are 

 somewhat larger and their margin is slightly elevated; the posterior third of joints 

 4-6 is of a lighter color than the rest of the body and very closely and quite coarsely 

 granulated, while the posterior third of abdominal joints 7 and 8 is polished and not 

 granulated. The last joint is very peculiarly formed; its tip is broad and prolonged 

 each side into a short, stout, and sharp tooth directed forward, and between these two 

 is a pair of slender and also bristle-like spines, directed forward and with their tips 

 curved in the shape of a loop; another pair of similar bristle-like spines, which are 

 directed forward and inward, are situated, one at each side, on a small projection at the 

 base ventrally of the stout lateral teeth, and between these is a large projection which 

 is armed at its edge with two large, stout, claw-like teeth, which stand at right angles 

 to the body of the pupa. The anal swelling is smooth, circular, and quite prominent; 

 the remaining portions of the tip are marked with coarse, elevated ridges, both dorsally 

 and ventrally. 



The pupa is shown in Phite V, below. 



EXPERIMENTS IN CONTROL. 



The following formula was used for spraying the infested Abutilon: 



Nicotine suliahate, 40 per cent ounce. . ^ 



■^liale-oil soap pound . . ^ 



Lukewarm water gallons. . 5 



The whale-oil soap was thoroughly dissolved in 5 gallons of water 

 and the solution, after the addition of the nicotine sulphate, was thor- 

 oughly agitated. The plants were sprayed in the morning w^liile some 

 dew remained on them, and in the form of a fine spray or mist from all 

 sides as well as from above and below, the idea being, if possible, to 

 reach every insect on the plants. The weather was calm and clear. 



Two days after this treatment about 95 per cent of the larvae were 

 found dead. Only four or five larvae were observed to be living, and 

 these, it is believed, came from adjoining unsprayed plants. In a 

 few days the plants began to take on a new appearance, putting out a 

 second growth of leaves. Unfortunately, however, three weeks after- 

 ward another lot of larvae attacked the same plants, although their 

 numbers were much less than on the occasion of the first attack. 

 They were, at the time of discovery, full grown and starting in to do 

 considerable injury. 



To complete the experiment, destroy the insects, and save the 

 plants, the same solution was applied again with the result that it 

 entirely eradicated all of the insects, and the Abutilon plants thrived 

 thereafter free from msect attack of any kind up to the end of the 

 season. (See PI. III.) It is believed that some of the insects were 

 in the egg stage when the spraying was made on the first occasion 

 and that they are not reached when in this condition. 



