Casey — A Revision of the American Paederini. 153 



developed aciculale teeth; eyes very small; neck barely two-flfths as 

 wide as the head; anterior tarsi scarcely thickened, not at all spongiose 



beneath; hind tarsi very slender, filiform. Europe *Micromedon 



Gular sutures more or less approximate, gradually converging and most 

 narrowly separated near the base of the head; species small to moder- 

 ately large in size, generally very finely, rather closely punctured and 

 only moderately shining; eyes very small; antennae moderately thick, 

 gradually enlarged distally; neck about two-flfths as wide as the head; 

 hind tarsi moderately slender. Palaearctic and Nearctic regions. .Medon 



11 _ Gular sutures convergingandmost narrowly separated basally; species 



small or moderate in size, of rather stout form, shining, the punctures 

 fine and well separated; antennae as in Medon; eyes well developed; 

 neck rather wide, almost half as wide as the head; prosternum only 

 carinate at the posterior cusp; elytra larger than the prothorax; pos- 

 terior tarsi moderately slender. Pacific coast regions Paramedon 



12 — Body moderately small in size, very slender, dull in lustre but not 



distiactly punctate, parallel, the elytra subequal to the prothorax ; gular 

 sutures widely separated; paraglossae coarsely, angularly bilobed, the 

 ligula simple at apex; palpi nearly normal, the second joint of the 

 labial compressed, the fourth joint of the maxillary small; antennae 

 moderate in length, slend>-r, filiform, not appreciably enlarged distally, 

 the third joint but little longer than the second, the first rather longer 

 than the next two combined though but little thicker; eyes very small; 

 neck unusually narrow, scarcely a third as wide as the head; proster- 

 num strongly carinate. Sonoran Medonodonta 



Body somewhat stout and more convex, moderately large in size, polished, 

 strongly but not densely punctured; gular sutures narrowly separated; 

 oral organs nearly as in the preceding, the eyes well developed; anten- 

 nae long, rather slender, feebly enlarged distally, the third joint dis- 

 tincily longer than the second, the first somewhat elongate but not 

 much thicker; neck two-fifths as wide as the head; elytra larger than 

 the prothorax; hind tarsi rather longer than usual, moderately slender, 

 the anterior noticeably dilated. Pacific coast regions Oxymedon 



13 — Gular sutures rather approximate, converging, most narrowly separated 



basally. Body moderately small in size, subdepressed, rather s^out, 

 subalutaceous, very finely, rather closely punctured, the elytra much 

 larger than the prothorax; lobes of the paraglossae rather obtuse at 

 apex; third maxillary palpal joint unusually infiated, somewhat com- 

 pressed and scarcely longer than the second; antennae rather thick, 

 feebly enlarged distally, the third joint but little longer than the second ; 

 eyes moderately developed; neck scarcely two-fifihs as wide as the 

 head; prosternum carinate; posterior tarsi short and rather thick, the 

 first joint almost as long as the next two combined, the anterior dis- 

 tinctly dilated; labrum with four large and conspicuous acute teeth, 

 the small deep rounded median notch with a minute obtuse denticle at 

 the bottom, the structure throughout nearly as in Polymedon. Appa- 

 lachian reg'on Tetramedon 



Gular sutures more or less widely separated, parallel or broadly arcuate, 

 becoming more widely divergent basally 14 



14 — Labrum with a small rounded median notch limited by the two inner 



