370 
Psyche 
[December 
Transeau (1941), Braun (1951), and Thomas (1951) believe that 
preglacial forests and associated animals have existed throughout the 
Pleistocene in the Allegheny Plateau within a short distance of the 
glacial boundary. Kemp (1979) suggests that the present distribution 
pattern of the primitive flightless Grylloblatta in western Canada was 
derived from stock that survived the Pleistocene glaciation relatively 
close to the glacial front, and that migration routes from Wyoming 
and Montana permitted refugium populations to reach their present 
locations. Alexander and Moore (1962) argue convincingly that peri¬ 
odical cicada populations survived in approximately their present 
locations. They believe the last glacial advance resulted in brood 
splitting of 17-year cicadas with the populations closest to the glacial 
border separating from their more southern members because of 
diapause summation resulting from repeated periods of exposure to 
Table 3. Duncan’s multiple range test for variable P/C (pulse number per chirp). 
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). *= colonies from which specimens have been collected (see Table 2). 
Colony 
number N Mean ± sd Grouping 
1* 
11 
13.6 
± 
2.9 
B 
A 
3* 
20 
9.4 
± 
1.9 
B 
9* 
10 
9.4 
± 
1.8 
B 
5* 
10 
8.5 
± 
1.4 
B 
8* 
10 
7.6 
+ 
0.7 
D 
4* 
10 
7.5 
± 
1.1 
D 
2* 
10 
7.5 
± 
1.7 
D 
11 
10 
7.4 
± 
0.9 
D 
10* 
10 
6.7 
± 
0.6 
E 
D 
7* 
10 
6.6 
± 
0.9 
E 
D 
6* 
10 
6.1 
± 
1.7 
E 
20 
10 
3.7 
± 
0.5 
F 
19 
10 
3.6 
+ 
0.6 
F 
18 
10 
3.5 
± 
0.5 
F 
14* 
10 
3.3 
± 
0.6 
F 
13* 
10 
3.3 
± 
0.6 
F 
15* 
10 
3.0 
± 
0.4 
F 
12* 
10 
2.9 
± 
0.6 
F 
17 
10 
2.8 
± 
0.7 
F 
16* 
10 
2.5 
± 
0.5 
F 
