176 Trans. Acad. Sct. of St. Louis. 
prothorax; under surface of the head convex, black, shining, though 
rather closely punctulate, the gular sutures well impressed, widely sep- 
arated, gradually converging nearly to the base of the head where they 
are separated by three-fourths of the maximum width of the third pal- 
pal joint. Male unknown; sixth ventral segment of the female strongly 
angulate at apex. Length 3.0 mm.; width0.62 mm. Arizona (Pinal 
Mts.), —Mr. Wickham...... Ved bbe ae SRE Ss dees eee ee pinalicum nu. sp. 
The species of Paramedon will prove to be very numerous, 
being also abundant in individuals as a rule, and, as the males 
seem to be as well represented as the females, it generally 
happens that male characters are at hand for use in identifi- 
cation. All of the species here described are represented by 
males except four, viz.: apacheanum, luctuosum, conforme and 
pinalicum, and these are sufficiently distinct in other ways by 
reason of well marked divergencies, either in structure or habi- 
tat, to render them easy of identification; conforme and 
luctwosum are, however, mutually rather closely related. In 
some parts of the series the species become closely allied and 
will require care and study in identification, as for example in 
the case of boreale and montanum, which may be distinguished 
from each other by some noticeable differences in the male 
sexual characters, as well as by the more sparsely punctate 
under surface of the head in the former. In general the 
species are smaller than those of Medon and are equally mo- 
notonous in general appearance. 
Medonodonta nt. gen. 
This genus and the succeeding are distinguished from those 
which precede in the group having the labrum bidentate, by 
the size and prominence of the teeth, which are very acute 
and project so far as to be conspicuous with an ordinary hand 
lens; they also have the neck somewhat narrower than usual, 
notably so in the present genus, the single representative of 
which may be defined as follows :— 
Slender, parallel and distinctly depressed, alutaceous in lustre and pale 
and uniform red-brown in color throughout; punctures obsolete except 
toward the side of the head and on the elytra, where they are very 
minute; head well developed, wider than long, the sides parallel and 
broadly, evenly arcuate, with the basal angles more than right but not 
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