92 
Psyche 
[June 
gree of adaptation attained by a cave inhabiting beetle is the degree 
of lengthening of the body and appendages. Measurements are used 
extensively here to document these lengths. All measurements are 
in millimeters and were made with a calibrated ocular micrometer. 
The antennal segment measurements give maximum widths, and the 
lengths do not include the basal bulb of articulation. 
I thank James Reddell for making this and other collections of 
Mexican Catopidae available to me for study. I also thank the many 
members of the Association for Mexican Cave Studies who have 
helped to collect these beetles. Professor Philip J. Darlington, Jr., 
kindly reviewed the manuscript. 
Ptomaphagus (Adelops) troglomexicanus n. sp. 
Figs. 1-5. 
Holotype. Known only from a unique male, (deposited in the 
Museum of Comparative Zoology, Harvard University, MCZ type 
number 31653), collected in Cueva de la Perra, at an elevation of 
2160 m (7100 feet), La Perra, 15 miles northwest of Gomez 
Farias, Tamaulipas, Mexico; 28 January, 1968; James Reddell, 
Robert W. Mitchell, Francis Rose, and John George collectors. 
Found in cave at base of flowstone slope. 
Description. Length 4.0 mm. Width 1.70 mm. Color dark 
brown. Shape oblong, very convex, narrowing posteriorly (Fig. 1). 
Metathoracic wings absent. Eyes small, diameter 0.13; facets present 
but indistinct (Fig. 2); pigment absent. Antennae long and thin, 
covering first third of elytra when laid back; club composed of last 
five segments; well supplied with abundant setae and with hairs 
at ends of segments. Segment measurements, lengths followed by 
widths; I, 0.34, 0.11; II, 0.22, 0.08; III, 0.29, 0.065; IV, 0.29, 
0.065; V, 0.26, 0.065; VI, 0.22, 0.08; VII, 0.22, 0.1 1 ; VIII, 0.13, 
0.09; IX, 0.18, 0.11; X, 0.18, 0.12; XI, 0.25, 0.1 1. Pronotum 
maximum width 1.66, one third before base; midline length 1.15; 
hind angles a little less than right, acuminate; front angles broadly 
rounded; base shallowly emarginate medial to hind angles; disc 
uniformly covered with short golden pubescense and transverse strigae. 
Elytra width 1.70, widest a little behind base; length 2.70; gradually 
narrowing in apical two thirds; apex rounded in male (female un- 
known) ; clothed with dense golden hairs; strigae oblique to suture. 
Hind tibia length 1.46, width at middle 0.13. Fore tarsi with first 
three segments swollen in male. Mid tarsi and hind tarsi normal. 
Hind tarsal segment lengths: I (basal) 0.56; II 0.31; III 0.25; IV 
0.22; V O.29; chord of arc of claw 0.13. Mesosternal carina low and 
