1968] 
Peck — Catopid Beetle 
93 
uniformly rounded. Aedeagus (Figs. 4, 5) long and thin; in dorsal 
view sides straight and parallel; in lateral view chord length 1.46, 
curved at base, straight in middle, tapering gently to tip; tip slightly 
acuminate in lateral and ventral views; five hairs on each side of 
ventral surface; parameres equal, bearing two hairs at ends. 
Diagnosis. The species is easily separated from all other Ptoma- 
phagus by the combination of the following characters; the pig- 
mentless but faintly faceted eyes whose maximum width is slightly 
less than a third the distance from the edge of the antennal socket 
to the lateral carina of the head, the thin elongate antennae covering 
the first third of the elytra when laid back, and the shape of the 
aedeagus. 
The abundant long pubescence of troglomexicanus may suggest 
a relationship to P. spelaeus (a Mexican cavernicole) P. giaquintoi 
Jeannel (a Guatemalan cavernicole) and an undescribed Guatemalan 
cavernicole. However, these last three species are one third smaller 
in body length. The aedeagus of the third species is as straight but 
not as thin as in troglomexicanus . The aedeagus has not been fig- 
ured or described for the other two species. 
The species groups of Ptomaphagus. The species described in 
this paper cannot at this time be placed in the phyletic groups of 
PtoTJiaphagus recognized by Jeannel (1949). Parts of his definitions 
are based upon female characters which are unknown for this spe- 
cies. Secondly, I have found some of Jeannel’s species groupings to 
be polyphyletic assemblages which have convergently reached similar 
levels of specialization. For instance, Jeannel places in the hirtus 
group P. hirtus Tellkampf (a troglobite from central Kentucky) 
and P. mitchellensis Hatch (a litter inhabitant from the Black 
Mountains of North Carolina). Both beetles posses similar shapes, 
but the very unusual aedeagus of mitchellensis demonstrates that it 
is distant from any other described North American Ptomaphagus. 
The aedeagus of hirtus indicates a close relation to P. nicholasi Barr 
and P. hubrichti Barr. These troglobitic species from Illinois and 
Tennessee respectively were unknown to Jeannel. I interpret the 
similarity of these three troglobites to be indicative of descent from 
a single ancestral species independently colonizing caves in the three 
states. 
In the future, it may prove necessary to recognize a separate species 
group to contain troglomexicanus and a similar-sized, undescribed 
species possessing small, pigmentless eyes and short, metathoracic 
wings. The latter is presently known only from a single female from 
a gypsum cave in the Mexican state of Nuevo Leon. 
