364 ENTOMOLOGICAL NEWS. [Dec., '06 



This was also true to a certain extent in oat fields. Clearly the 

 bugs preferred a soil with numerous cracks in which they 

 might hide and oviposit. This being the case, it seemed prob- 

 able that if a liberal application of tobacco dust were applied 

 to each hill of corn they might be driven off. Field experi- 

 ments were therefore instituted to test the value of this remedy. 

 It was found that where strong winds did not blow the dust 

 away the bugs were almost entirely killed by it, a dozen or 

 so being found dead at each hill. Usually in about an hour 

 after application the bugs remaining at the hill were stupefied. 

 The action of the tobacco dust on these insects is rather 

 unique, being comparable to a moth flying to its death in a 

 flame, for both are the result of tropisms. 



The chinch bug seems to be very clearly and decidedly 

 stereotropic, to use the term coined, I believe, by Prof. Jacques 

 Loeb. Possibly they are also geotropic, but this is not so clear. 

 In other words, the chinch bug has an instinctive attraction for 

 a crevice or coarse loose soil. This is incidental with the ovipo- 

 sition of the hibernated brood. Neither geotropism or nega- 

 tive heliotropism seem to explain the phenomena. That an 

 insect should so instinctively remain in a substance which 

 soon causes its death, and the odor of which is enough to drive 

 many insects from plants, seemed so unusual that some labora- 

 tory experiments were made to further show this point. ' May 3, 

 1903, Mr. Wilmon Newell placed 27 adult bugs in a box and 

 covered with tobacco dust. After two and one-half hours the 

 dust was removed, none having escaped, though they might 

 easily have done so, the box being uncovered and the dust 

 shallow ; of the 27 but 7 revived. Thirty bugs were similarly 

 placed under tobacco dust the same day for three hours, but one 

 of them reviving. Twenty-one bugs were placed in a small box 

 and covered a half inch deep with tobacco dust. Three crawled 

 out. Four others crawled to the surface, two remaining upon 

 it and two crawling back in the dust. At fifteen minutes all 

 were stupefied. At end of seventeen minutes three bugs were 

 removed from the box and placed on the table. In sixty 

 minutes one crawled off, and in eighty minutes another revived. 

 Twenty-two minutes after the experiment was started, five 



