34 
Psyche 
[March 
Species differences in the sounds made by the male are 
frequently detectable by the human ear, and Fulton (1952) 
TABLE II — Crossing experiments after removal of the 
tegmina of the males at the base, wings left intact. 
Sperms 
Code 
Cross 
Eggs Developed 
Found ( + ) in 
No. 
( + ) or Failed 
Spermatheca 
to Develop ( — ) 
or Not 
Found ( — ) 
Cl 
Canadian 
X 
Canadian 
+ 
C2 
Canadian 
X 
Canadian 
+ 
C3 
Canadian 
X 
Pakistani 
■ — 
C4 
Canadian 
X 
Pakistani 
■ — 
C5 
Pakistani 
X 
Canadian 
— 
C6 
Pakistani 
X 
Canadian 
■ — 
C7 
Pakistani 
X 
Pakistani 
+ 
has characterized one of his races of the field cricket on 
the basis of its song. It seemed possible that the mating 
sounds of the male were responsible for the unattractive- 
ness of the males to the females of the other strain of 
A. domesticus, although no differences between the strains 
were apparent. The tegmina of the males of both strains 
were accordingly severed at the base, leaving the wings 
intact (the removal of the tegmina did not appear to affect 
the normal activities of the males), and crossing experi- 
ments were carried out as shown in Table II. 
Females mated with males of the same strain laid 
fertilized eggs and the spermatheca of one female was 
found to contain sperms, whereas females mated with 
males of the other strain laid eggs which invariably failed 
to develop, and no sperms were found in the spermatheca 
of the one female examined. Thus the stridulation of the 
participating male is not necessary for copulation (or, 
more precisely, insemination), nor is it the sole discourage- 
ment to copulation in crosses between strains. 
