Key to the Genera of Xanthopyginae

1. Last segment of labial palpus hemispherical. . . . . . . . Tympanophorus Nordmann

Last segment of labial palpus sub cylindrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 2

2(1). Middle coxae widely separated. . . . . .. . . .. . . . . . . . . . . . . . . . . . .. . .Creophilus Leach

Middle coxae contiguous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3 (2). Elytra dehiscent, sutures overlapping. . . . . . . . . . . . . . . . . . . . . .Thinopinus LeConte

Elytra not dehiscent, sutures not overlapping. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. 4

4(3). Infraorbital ridge absent; foreparts impunctate. . . . . . . . . . . . . . . . . . . Hadrotes Mäklin

Infraorbital ridge present; foreparts coarsely punctate. . . . . . . . . . . Xanthopygus Kraatz

A specimen from Texas, which fits well the description of Trigonopselaphus subcoeruleus LeConte, has the anterior tarsus very narrowly dilated whereas both Nordmann and Erichson describe it as being greatly dilated in that genus. Alfred Newton has examined the type of subcoeruleus and has expressed the opinion (personal communication, Ian Moore & E. F. Legner) that it is not congeneric with Trigonopselaphus. Consequently, that genus is not included in the above key as probably not being found in this region. The genus to which subcoeruleus belongs has not been determined.

Key to the Genera of Staphylininae

1. Superior lateral line of pronotum not deflexed in front so that the large lateral setigerous

puncture is on it or separated from it at most by little more than the width of the puncture. . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . .. 2

Superior lateral line of pronotum deflexed in front so that the large lateral setigerous puncture

is distant from it by at least three times the width of the puncture . . . . . . . . . . . . . . . . . . . .4

2(1). Last segment of labial palpus not or very little narrower than pen-ultimate, subfusiform or

acticulate; anterior tarsus usually with pale spatulate setae beneath. . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Philonthus Stephens

Last segment of labial palpus narrower than penultimate, cylindrical; tempora longer than

eyes, subparallel; pronotum elongate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. .. 3

3(2). Anterior tarsus broadly dilated, with pale spatulate setae beneath; pronotum with a series

of four discal punctures each side of mid-line . . . . . . . . . . . . . . . .Gabronthus Tottenham

Anterior tarsus not dilated; without pale spatulate setae beneath; pronotum with a series of

five discal punctures each side of mid-line. . . . . . . . . . . . . . . . . . . . . . . . Gabrius Curtis

4(1). Prosternum not carinate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Prosternum strongly longitudinally carinate. . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . 10

5(4). Basal impressions of basal tergites not more coarsely punctured than rest of tergite. . . . 6

Basal impressions of basal tergites much more coarsely punctured than rest of tergite

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Neobisnius Ganglbauer

6(5). First segment of posterior tarsus as long as last segment.. ... . . . . . . . . . . . . . . . . . ... 7

First segment of posterior tarsus shorter than last segment . . . . . . . . .Erichsonius Fauvel

7 (6) . Anterior tarsus dilated (second segment wider than long), with dense pale spatulate

setae beneath. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Anterior tarsus slender (second segment longer than wide); without pale spatulate setae

beneath; posterior femora of male usually spinose beneath. . . . .Belonuchus Nordmann