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[Vol. 85 
Table 2. Effect on terminal volley frequency (C), in abdominal strokes/sec, of 
artificially mass-loading the abdomen of three males and one female of Ch. plora- 
hunda. Weight gains are tabulated in column 3; the last column lists n. the number of 
volleys measured. Equivalent frequencies (at 27°C) in column six were calculated 
from the slope of regression line C in Fig. 3. Superscript “x” denotes lab-reared 
insects. 
Weight. 
mg. 
Temp.. 
°C. 
Vibration 
frequency. ±SD 
Equivalent 
at 27°C. 
n 
Male 1 
control 
7.5 
26.8 
39.78 ± 1.83 
39.98 
29 
mass-loaded 
9.0 
30.0 
47.08 ± 1.84 
44.00 
20 
Male 1" 
control 
6.7 
27.1 
44.49 ± 2.44 
44.51 
20 
mass-loaded 
8.5 
27.0 
44.59 ± 3.52 
44.59 
25 
Male 2^ 
control 
7.2 
27.3 
45.98 ± 2.44 
45.60 
36 
mass-loaded 
8.5 
26.8 
44.92 ± 2.80 
45.15 
36 
Female 1 ' 
control 
9.6 
27.3 
43.47 ± 2.31 
43.20 
28 
mass-loaded 
10.6 
27.0 
43. 14 ± 2.50 
43.14 
19 
and pulse (=wing stroke) rates went to zero at about 4°C when their 
temperature regressions were extrapolated downward. The same 
phenomenon can be seen in other insects, as well, including several 
tettigoniids studied or reported by Dumortier (1963), Shaw (1968), 
and Whitesell and Walker (1978) and two delphacid homopterans 
studied by Booij (1982). Temperature data for initial volley frequency 
and volley repetition rate of lacewing calls are also reasonably 
consistent with the concept of regression convergence, since the 
x-intercepts for relevant call parameters range from 2.82° C to 
9.40° C in Ch. plorahunda and average 8.3 1°C in Chrysopa 
oculata (Henry 1982b). However, the flatter slopes of the temperature- 
frequency regressions for middle and terminal portions of plora- 
bunda volleys cause those lines to intersect the x-axis at — 1.27°C 
and -19.09°C, respectively, which does not fit well with Walker’s 
generalization. Moreover, other examples from the literature fail to 
confirm the phenomenon, even in certain crickets and katydids 
recently studied by Walker himself (and collaborators): for instance, 
Anurogryllus arhoreus and winter races of Neoconocephalus triops 
both display rather flat regression lines of temperature versus wing 
stroke rate that intersect the x-axis well below — 5°C (Prestwich and 
Walker 1981, Whitesell and Walker 1978). Thus, Walker’s “four 
