364 
Psyche 
[December 
lected from the northern (Pennsylvania to Virginia), southern (South 
Carolina to Florida), and southwestern (Oklahoma, Arkansas, 
southwest Missouri) ranges of P. c. camellifolia. Apparent intergra¬ 
dation of subgenital plate dimensions, along with similar appearance 
of male cerci in southeastern material and specimens from Pennsyl¬ 
vania, precluded his recognizing these three populations as sub¬ 
species. 
Alexander (1956) noted that specimens from Ohio and North 
Carolina differ in the shape of the male subgenital plate and pulse rate 
of the calling sound. Subsequently, on the basis of these differences, 
Alexander and Shaw (unpublished) differentiated three populations. 
Two of these probably correspond to Hebard’s (1941) northern and 
southern populations of P. c. camellifolia. A third population, whose 
geographic distribution has not been determined in detail, occurs in 
Louisiana, Mississippi, southwestern Georgia and probably Tennes¬ 
see. On the basis of intergradation in calling sound parameters (pulse 
rate and chirp pulse number), and subgenital plate dimensions, Alex¬ 
ander and Shaw hypothesized a zone of hybridization, forming an 
inverted Y-shape, among the three populations (Alexander 1968). 
Shaw and Carlson (1969) used differences in chirp length of calling 
sounds and length of male subgenital plate to distinguish two popula¬ 
tions of P. camellifolia in Iowa. For one population, representing the 
westward extension of the northern population of Alexander and 
Shaw, they reported subgenital plate lengths of 11.8 to 13.2 mm and 
two- to three-pulse chirps. A previously unreported western popula¬ 
tion in Iowa possesses subgenital plates 14.7 to 16.8 mm in length and 
chirps of 8 to 15 pulses. 
Shaw and Carlson’s (1969) characterization of the two populations 
of P. camellifolia was based on relatively little data; namely, song 
records from three counties (Boone, Hardin, Story), and subgenital 
plate measurements from 13 specimens representing seven counties 
(Boone, Hardin, Linn, Marion, Story, Van Buren, Worth). Since this 
publication we have been unable to confirm two of the geographic 
locations of western P. camellifolia based on subgenital plate meas¬ 
urements of specimens in the Iowa State University insect collection. 
Several visits to Worth County failed to uncover any P. camellifolia 
in this northern county. We have heard only northern males singing 
in Van Buren County in southeast Iowa. 
