Tragidion

Swift, Ian & Ray, Ann M., 2008, A review of the genus Tragidion Audinet-Serville, 1834 (Coleoptera: Cerambycidae: Cerambycinae: Trachyderini), Zootaxa 1892, pp. 1-25 : 21-22

Key to the males of Tragidion species

Within this key, T. coquus can key out in three different couplets, due to the variability of phenotypes. Populations from western and central Texas do not key out well (see discussion). Also note that the males of T. carinatum is unknown and does not appear in the key.

1 Elytral surface with elevated costae, surface appearing corrugated ....................................................... 2

1’ Elytral surface smooth, striae not appearing elevated ............................................................................7

2(1) Elytron with 5 costae ..............................................................................................................................3

2’ Elytron with 4 costae ..............................................................................................................................4

3 (2) Integument of head, pronotum, scape and sometimes legs generally light red-brown; elytra narrowing to apex, costae somewhat curved inward to suture ( Fig. 3 D) ................................................. densiventre

3’ Integument of head, pronotum, legs and scape black; elytra parallel-sided, costae generally straight from base to apex ( Figs 2 E–F) ....................................................................................................... coquus

4(2’) Antennomeres 4–11(or 4–12 in species with 12 antennomeres) not annulated with orange, thin; lateral pronotal tubercles reduced; body somewhat elongate...........................................................................10

4’ Antennae annulated with orange; body robust, lateral pronotal tubercules pronounced.........................5

5(4’) Elytra with broad, dark basal band, exceeding the scutellum by at least 2 × its length; elytral costae terminating at ½ to apex ( Fig. 3 B) ................................................................................................. deceptum

5’ Elytra with narrow, dark basal band not or barely exceeding the scutellum; elytral costae terminating at the apex or nearly so................................................................................................................................6

6(5) Ventral surface, head, and metalegs clothed in pubescence with bright metallic blue reflections; pubescence of metatibia, long and dense ( Fig. 1 C) ........................................................................... annulatum

6’ Ventral surface, head, and metalegs clothed in pubescence with at most dull blue reflections; pubescence of metatibia, somewhat dense, short ( Figs 2 E–F) ................................................................ coquus

7(1’) Body elongate and narrow, greater than 3 × as long as elytral humeri; ventral and head pubescence distinctly tinged with bright metallic blue reflections; antennae long, with at least 5 entire antennomeres exceeding the elytral apices, the 3rd antennomere attaining the humeri ( Fig. 2 C) ........................ bicolor

7’ Body robust, less than 2.5 × as long as elytral base; ventral and head pubescence not tinged with metallic blue reflections; antennae with at most 3 entire antennomeres exceeding the elytral apices, the 3rd antennomere not attaining the humeri.....................................................................................................8

8(8’) Metatarsi slender, the 1st tarsomere longer than the following two together, and 2nd tarsomere longer

than broad and distinctly more elongate than the 3rd; scape robust, greater than 2 × the width of the 2nd antennomere at apex, antennomeres 7–11 entirely black ( Fig. 4 B) .......................................... gracilipes 8’ Metatarsi robust, the 1st tarsomere almost as long as broad, not as long as the following 2 tarsomeres; scape not as robust, less than 1.5 × the width of the antennomere 2 at apex, antennomeres 8–11 entirely black or brown.........................................................................................................................................9

9(9’) Antennae generally unicolorous brown; integument of head, legs, pronotum, and scape reddish-brown; pronotal pubescence brown; elytra tawny-tan; antennae with at least 3 entire antennomeres exceeding the elytral apices ( Fig. 1 A).............................................................................................................. agave

9’ Antennae distinctly annulated in orange; integument of head, pronotum, legs and scape black; pronotal pubescence black; elytra yellow-orange; antennae with 2 entire antennomeres or less exceeding the elytral apices ( Fig. 1 E).................................................................................................................... armatum

10(4) Antennae with 12 antennomeres, 5–7 producing a distinct, recurved apical spine; metafemora with very dense, long, erect, hairs with metallic blue reflections; pubescence of head and ventral surface tan ( Fig. 3 F) ..................................................................................................................................... dichromaticum

10’ Antennae with 11 antennomeres, 5–7 not producing distinct, recurved apical spine; metafemora moderately clothed in short hairs with dull or no metallic blue reflections; pubescence of head and ventral surface black ( Figs 2 E–F) ................................................................................................................... coquus

Figures

FIGURE 1. Dorsal habitus photos of Tragidion spp. A, Tragidion agave (male); B, T. agave (female); C, T. annulatum (male); D, T. annulatum (female); E, T. armatum (male); F, T. armatum (female).

FIGURE 2. Dorsal habitus photos of Tragidion spp. A, Tragidion auripenne (male); B, T. auripenne (female); C, T. bicolor (male); D, T. bicolor (female); E, T. coquus (male); F, T. coquus (male).

FIGURE 3. Dorsal habitus photos of Tragidion spp. A, Tragidion coquus (female); B, T. deceptum (male); C, T. deceptum (female); D, T. densiventre (male); E, T. densiventre (female); F, T. dichromaticum (male).

FIGURE 4. Dorsal habitus photos of Tragidion spp. A, Tragidion dichromaticum (female); B, T. gracilipes (male); C, T. gracilipes (female).