1968] 
Peck — Catopid Beetle 
95 
Discussion. A comparative indication of the degree of cave adap- 
tation possessed by P. troglomexicanus is given in Table I. 1 he 
species is compared to an epigean, a troglophilic, and a troglobitic 
species from the eastern United States: P. consobrinus Leconte is 
found in eastern North America from Massachusetts to Iowa south- 
ward to Florida and eastern Texas. It is a winged, eyed, forest 
litter-inhabiting species. P. cavernicola Schwarz is a winged, large- 
eyed species known only from caves in a large arc from Florida to 
the Ozarks and eastern Iowa down to central Texas and into north- 
ern Nuevo Leon, Mexico. Though it can fly, it is apparently limited 
to caves by ecological factors. P. loedingi Hatch is a wingless species 
whose eyes are reduced to small, unpigmented, vaguely faceted 
areolae. It occurs limited to caves in the vicinity of Huntsville, 
Alabama. 
As the table shows^ in this series of species, in a comparison of the 
ratios of length to width of three selected appendage segments the 
numerical value increases as the species becomes more cave limited. 
P. loedingi possesses a more slender hind tibia, but troglomexicanus 
possesses a more slender third antennal segment and first segment 
of the hind tarsus. These differences may or may not prove to be 
significant when the range of variation is learned for each species. 
L/W 
FSHTar 
L/W 
HTib 
L/W 
TAS 
EW/HW 
P. consobrinus 
Jefferson Co., Mo. 
4.5 
8.0 
1.25 
.670 
P. cavernicola 
Marvel Cave, Mo. 
7.8 
9.7 
2.60 
.650 
P. loedingi 
Shelta Cave, Ala. 
9.0 
12.0 
3.60 
.290 
P. troglomexicanus 
10.0 
10.7 
4.50 
.370 
Table 1. Ratios of measurements of a specimen of four species of North 
American Ptomaphagus, showing comparative lengths of appendage sections 
and the size of the eye. Abbreviations: EW/HW, horizontal eye width 
divided by width of head between edge of antennal socket and lateral 
edge of head; FSHTar, first segment of hind tarsus; HTib, hind tibia; 
L/W, length divided by maximum width ; and TAS, third antennal segment. 
Explanation of Plate 4 
Figures 1-5. Holotype male of Ptomaphagus troglomexicanus, from Cueva 
de la Perra, Tamaulipas, Mexico. Fig. 1, dorsal view of adult, hairs and 
strigae omitted. Fig. 2, side view of head showing small pigmentless eye. 
Fig. 3, ventral surface of genital segment. Fig. 4, ventral view of tip of 
aedeagus. Fig. 5, lateral view of aedeagus. 
