ASSEMBLING. 353 



Experiment No. 17. 



August 1. A can containing four unfertilized females, 

 with the last three segments of the abdomen coated entirely 

 with shellac, was exposed as in the previous experiments, 

 and was visited by twelve males from 10.15 A.M. to 4 P.M. 



Experiment No. 18. 



August 1. Another can, containing four unfertilized 

 females, which were coated with shellac over the whole 

 body, with the exception of the three posterior segments, 

 was exposed under the same conditions as in the preced- 

 ing experiments, and was visited by twenty-six males from 

 10.15 A.M. to 4 P.M. 



Experiment No. 19. 



August 1. A can containing four unfertilized females, 

 with the tips of their abdomens covered with shellac, so as 

 to close the external openings of the body, was exposed 

 under the same conditions as in the preceding experiments, 

 and was visited by eleven males from 10.15 A.M. to 4 P.M. 



Experiment No. 20. 



August 2. A single unfertilized female, in normal con- 

 dition, was placed in a small cardboard box, having a cheese- 

 cloth top, and exposed on the branch of a tree, at a distance 

 of five feet from the ground. This box was visited by 

 twenty-eight males from 10.30 A.M. to 3 P.M. 



Experiment No. 21. 



August 2. A wire-gauze can, containing an unfertilized 

 female that had been denuded of hair, but whose wings were 

 in a normal condition, was exposed under the same con- 

 ditions as in the preceding experiments, and was visited by 

 thirteen males from 10.30 A.M. to 1 P.M. 



Experiment No. 22. 



August 2. This experiment was conducted under the same 

 conditions and at the same time as preceding experiments, 



