206 PROCEEDINGS OF THE NATIONAL MUSEUM vol.108 



by Bollman (1888) measures 70 mm. in length and 15 mm. in width. 

 Distribution: P. c. denticulatus is known only from the Piedmont 

 region of north-central Georgia. Aside from the type locality, the 

 only known station is Indian Springs, Bibb County, Ga., where a 

 single male was collected by Prof. Lucien M. Underwood. Unfortu- 

 nately the gonopods of this individual were removed and lost at some 

 time in the past, making a conclusive determination impossible. How- 

 ever, considering the proximity of Indian Springs to Atlanta, and 

 the similarity of size and structure in specimens from the two places. 

 I think that my allocation will eventually be verified by collections 

 made in the region concerned. 



Pachydesmus crassicutis duplex Chamberlin 



FiGUKES l,d, 5,e,/, 7,6, 8,6, 



Pachydesmus duplex Chamberlin, 1939, p. 5, fig. 8. — Chamberlin and Hoffman, 

 1958, p. 43. 



Type specimen: Male holotype (RVC), from Grenada, Grenada 

 County, Miss., collected in July 1910 by Dr. Chamberlin. 



Diagnosis: A medium-sized member of the crassicutis phratry, 

 characterized by the long, slender, simple secondary tibiotarsus, which 

 completely lacks any remnant of the subapical process and which 

 equals or slightly exceeds the primary branch in length. The cypho- 

 pods are distinct from those of members of the laticollis phratry in that 

 the receptacle is roughly triangular in mesial aspect, its distal end 

 acuminate and considerably exceeding the ends of the valves. In life 

 the color is dilute black, with clear yellow paranotal maculae. 



Variation: Four adult specimens studied showed the normal range 

 of variation in size. The largest is the male holotype, with a length of 

 72 mm. and a width of 15 mm. The other thi'ee specimens, a male 

 and two females, measure 61 and 59 mm. in length, respectively. 

 The male, from Memphis, Tenn., differs slightly from the holotype in 

 that the secondary tibiotarsus is slightly sinuous instead of nearly 

 straight, but this can at present be considered little more than within 

 the normal range of variability. 



Distribution: P. c. duplex appears to be endemic to the upper half 

 of the Cretaceous embayment region in northern Mississippi and 

 western Tennessee. It seems probable that collecting in the futm'e will 

 reveal the presence of the subspecies in the western tip of Kentucky. 

 Specimens have been examined as follows: 



Mississippi. Grenada County: Grenada, 1 cf (holotype), July 1910, R. V. 

 Chamberlin (RVC). Marshall County: Holly Springs, 1 9 , Sept. 17, 1955, L. 

 Hubricht (RLH). 



