HARPALINVE 237 



Tachycellus Moraw. 



No one seems to have ever had more than a vague notion as to 

 what the genus Tachycellus of Morawitz might really be. Chau- 

 doir assigned to it such an incongruous mixture that it was 

 entirely rejected by LeConte in his treatment of our minute Har- 

 palids (Proc. Acad. Phila., 1868, p. 379). Afterwards G. H. Horn 

 conceived the idea that it included all those forms having three 

 glabrous antennal joints, but, as pointed out by Fall, the warrant 

 for that assumption is not clear. There exists, however, at the 

 present time, a tradition that there must be three glabrous antennal 

 joints and furthermore that the Harpalus nigrinus of Dejean, is a 

 typical exponent of the genus. Accepting this as true, there is no 

 other species than nigrinus that can properly form part of Tachy- 

 cellus, because of a peculiarity in the form of the frontal foveae 

 stated in the above table of genera; the other species placed in 

 Tachycellus by Horn, will therefore have to form another genus, to 

 which the name Triliarthrus is here assigned. The mental emargi- 

 nation is relatively narrow and deep and the tooth strong, with its 

 acutangular apex blunt at tip. The ligula is feebly dilated apically, 

 the paraglossse attached nearly throughout its length but having 

 their external angle at apex narrowly prolonged, as in some of the 

 Anisodactylini. The assumed type of the genus may be described 

 as follows: 



Form oblong, moderately convex, very shining, deep black and without 

 metallic lustre, the under surface and femora black, the tibiae pale, 

 black apically, the tarn black; head rather small, barely three-fifths 

 as wide as the prothorax, rather constricted at base and with moder- 

 ately prominent eyes; antennae slender, black, with pale basal joint, 

 the third joint virtually glabrous, though with pallid setae; prothorax 

 transversely quadrate, a third to two-fifths wider than long, feebly 

 rounded at the sides and widest anteriorly, the sides very feebly 

 converging and straight thence to the basal angles, which are but 

 little more than right and sharply marked though not prominent; 

 base transverse, strongly beaded laterally, the bead interrupted in 

 median half, very slightly wider than the sinuato-truncate apex; 

 surface smooth, finely, evenly reflexed at the sides and with a 

 distinct median stria from the obsolescent anterior impression to 

 the base, the foveae linear, a third the total length, rather deep 

 though impressed and not evidently punctate; elytra relatively 

 large, one-half longer than wide and one-half wider than the pro- 

 thorax, parallel, with feebly arcuate sides and obtusely rounded 

 apex, the sinus almost obsolete; striae very fine, not deep though 



