176 Trans. Acad. Sci. 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.; width 0.62 mm. Arizona (Pinal 

 Mts.), — Mr. Wickham pinalicnm n. 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, hictuosum, conforme and 

 pinalicnm , 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 

 luciuosum 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 maybe 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 n. 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 



