368 
Psyche 
[December 
because the groups delineated by this character were the same as by 
SPL. For population diagnosis, SPL would be simpler to measure 
than SPSL. 
Duncan’s test for P/C delineates the same two groups (Table 3) as 
analysis of SPL (Table 2). However, in the former case, additional 
colonies are included in both groups because specimens were not 
collected from all colonies. Western katydids, those with long sub¬ 
genital plates (colonies 1-10; Table 2), produce long chirps (colonies 
1-11; Table 3). In contrast, northern katydids, those with short 
subgenital plates (colonies 12-16), produce short chirps (colonies 
12 - 20 ). 
Table 2. Duncan’s multiple range test for variable SPL (subgenital plate length). 
Means with the same letter and overlapping ranges of means designated by two or 
more letters are not significantly different. The range of means designated F are 
significantly different from overlapping range of means designated A, B, C, D and E (p 
< .05). 
Colony 
number 
N 
Mean ± sd (mm) 
Grouping 
4 
11 
17.2 ± .5 
A 
2 
25 
16.8 ± .6 
B A 
3 
23 
16.6 + .6 
B C 
9 
4 
16.4 ± .2 
B D C 
5 
35 
16.4 + .8 
D C 
10 
42 
16.3 + .5 
D C 
1 
9 
16.2 + .5 
D C 
7 
4 
15.8 ± .6 
E D C 
6 
7 
15.2 + .3 
E D 
8 
5 
15.1 + .2 
E 
16 
5 
13.0 ± .5 
F 
13 
8 
13.0 ± .5 
F 
12 
11 
12.9 ± .4 
F 
15 
6 
12.4 + .2 
F 
14 
10 
12.2 ± .3 
F 
All 40 males collected from colonies believed to be members of the 
northern population have cerci the ventral arms of which bifurcate 
with dorsal and ventral arms pointed distally (Fig. 2A). In contrast, 
135 of 165 males from the western population showed a slightly 
bifurcate, blunt ventral cereal arm (Fig. 2B). The remaining 30 males 
exhibited various cereal shapes (e.g., Figs. 2C and 2D), making them 
indistinguishable regarding population affiliation. 
