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Psyche 
[December 
of the ventral segments of the female where the copulatory 
slit is located (Fig. 2). They remain in this position any- 
where from one to several minutes. 
No attempt was made by previous observers to establish 
the facts as to how the male locates the female, and what 
tropic reactions govern the act of copulation, which is so 
unique in this insect. In the following paragraphs, the re- 
sults of a study are given wherein the writer attempts to 
discover some of the facts regarding this problem. 
In some insects, chemotropic reactions are of extreme 
importance in bringing together the two sexes of the same 
species for mating purposes. Mayer (1900) demonstrated 
what attracting force the odor from the female of the C. 
prometha moth has upon the male. In the case of the Jap- 
anese beetle, the female apparently diffuses some odor 
which is attractive to the males. On several occasions, the 
writer observed in the field, early in the season, over twenty 
males clustered around one female. Several of these males 
were attempting to mate with each other, a phase which will 
be discussed later. The ball-formed cluster, with the female 
in the center, would lead one to believe that some odor 
emanating from her attracted all these males. However, 
observations and experiments described below indicate that 
the “smell mind” idea cannot be applied in the case of 
Cimex lectularius. 
A female approached a male from the rear and remained 
in this vicinity for a long time, yet the male did not per- 
ceive her. Only when the female passed in front of the male 
did the latter take cognizance of her and soon made at- 
tempts to mate with her. Such observations occurred upon 
other occasions. If odor signals the presence of a female, 
its effects should be manifested regardless of the position 
of the female, as long as she is in the proximity of the male. 
This did not seem to be the case in the above-mentioned 
observations. In order to verify these casual observations, 
the following experiments were conducted. 
Five females were placed in a vial, 2 cm. in diameter 
and a piece of cheese-cloth was spread and fastened over 
its opening. This was then turned upside down so that 
the cloth served as the foothold for the five bugs; it was 
