Key to the New World Hylurgops

1 Pronotum slightly wider than long (0.92 ± 0.4, N=109), distinctly constricted anteriorly (Fig.14 a); mature color reddish-brown to dark brown, never black............................................................................. 2

- Pronotum slightly longer than wide (1.04 ± 0.4, N=118), not constricted but smoothly tapering anteriorly (Fig. 14 b); mature color dark reddish-brown to black........................................................................ 5

2(1) Smaller species (2.5–3.4 mm); declivital apex upturned (Fig. 15 a); elytral striae more distinctly impressed; granules larger; mature color brown to reddish-brown................................................. palliatus (Gyllenhal, 1813)

- Larger species (3.7–5.6 mm); declivital apex rounded, not upturned; elytral striae less distinctly impressed; declivital granules smaller; mature color brown to black...................................................................... 3

3(2) Dorsal surfaces dull; pronotal interspaces coarse, punctures deep; mature color brown, reddish brown to black; distribution Trans-Mexican Volcanic Belt to high mountains in southern Honduras ..................... planirostris (Chapuis, 1869)

- Dorsal surfaces lustrous to semi lustrous; pronotal interspaces smooth, punctures shallow; mature color reddish-brown to deep dark-reddish brown; distribution Alaska to New Mexico ...................................................... 4

4(3) Pronotum interspaces distinctly reticulate (Fig. 16 a), large punctures less than twice the diameter of small; declivital interstriae granules evenly separated, declivital granules vested with a long, hair-like setae; averaging shorter (4.2 mm); distribution coastal from Alaska to southern California......................................... rugipennis (Mannerheim, 1843)

- Pronotum interspaces smooth to granulate (Fig. 16 b), large punctures more than double the diameter of small; several declivital interstriae granules absent or very small, declivital granules vested with a short, hair-like setae; averaging longer (4.6 mm); distribution transcontinental, from northern British Columbia to Nova Scotia south to Arizona and North Carolina............................................................................................. pinifex (Fitch, 1858)

5(1) Pronotum with distinct, long, erect, hair-like setae........................................................... 6

- Pronotum with indistinct, short, recumbent hair-like setae.................................................... 7

6(5) Pronotum base nearly as wide as body, diameter of large punctures only twice diameter of smaller middle line not raised; hairlike setae yellow to reddish-yellow; distribution Arizona and New Mexico to northern Honduras and El Salvador ....................................................................................... incomptus (Blandford, 1897)

- Pronotum base distinctly narrower than body, diameter of large punctures more than twice diameter of smaller, middle line raised; hair-like setae whitish; distribution Central Mexico ............................. longipennis (Blandford, 1896)

7(5) Pronotum with abundant, similar sized punctures, large less than twice diameter of small punctures; ventral vestiture short...................................................................................... knausi Swaine, 1917

- Pronotum with few, differently sized punctures, large twice diameter of small; ventral vestiture long................... 8

8(7) Elytral surfaces dull, entirely, distinctly reticulate, visible at 30× magnification; pronotum longer (1.07 ± 0.03); body length averaging longer (4.5 mm)............................................................ reticulatus Wood, 1971

- Elytral surfaces smooth and glossy, varying from granulate to reticulate on basal third of elytra; pronotum shorter (1.03 ± 0.04); body length averaging shorter (4.0 mm)........................................... porosus (LeConte, 1868)