334 EDWARD F. ADOLPH 
2. Texture. The pulpy consistency of overripe fruit was imi- 
tated more or less closely by other substances. The flies re- 
sponded fairly well to solidified agar and water, and less freely 
to boiled starch and to the gelatinous material which envelops 
the eggs of amphibians (table 2). 
3. Taste. Solutions of non-odorous substances were absorbed 
in cotton and placed in vials with the flies, where free contact 
was allowed. In the presence of glucose and sodium chloride a 
few eggs were laid (table 2). 
4. Odor. Flies subjected to the influence of odorous substances 
in solution were prevented from contact with the solutions by 
partitions of cheesecloth, or of perforated blotting-paper, or 
filter-paper. No moisture was within reach of the flies. The 
flies responded to a small extent to solutions of acetic acid plus 
aleohol, formic acid, acetic acid, butyl alcohol, and fermenting 
banana (table 2). 
5: Taste and odor. Without intervening partitions, slightly 
larger responses were given to odorous substances in solution 
(table 2). 
6. Texture and odor. Moist surfaces of various kinds and 
inaccessible odorous substances were presented at one time, and 
these combinations constituted a large number of experiments. 
The surfaces to which the flies responded were, as shown in table 
2, water, clay and water, boiled starch paste, and agar jelly. 
The odorous substances accompanying these varied the magni- 
tude of the results. 
7. Texture, taste, and. odor. Finally all the experimental 
stimuli were allowed to influence the flies at one time. The few 
substances tried all called forth responses; they were fermenting 
banana and fresh banana (table 2). 
Summary. From these experiments it is evident that stimuli - 
may be roughly evaluated according to their ability to induce 
egg-laying. This may be represented as in table 3. 
Other observations. The concentration of the odorous sub- 
stances was found to have no influence upon the response, ex- 
cept where the concentration of a toxic substance was great 
enough to kill the flies, as ethyl acetate did. When stimulating 
