Geraeus, PASCOE AND, 1889

Prena, Jens, 2009, A Review of the Species of Geraeus Pascoe and Linogeraeus Casey Found in the Continental United States (Coleoptera: Curculionidae: Baridinae), The Coleopterists Bulletin 63 (2), pp. 123-172 : 127-130

Key to Geraeus and Linogeraeus Species in the Continental United States

1. Prosternum with posterior line of anterior tubulate portion modified, usually with longitudinal fold in front of coxae and deep punctures on one or both sides ( Figs. 1–4 ), small-sized species often without folds but with two separate, rather deep punctures in middle; prosternum with vestiture on median line directed backwards, not radiating from central point; larger-sized species (. 3 mm) with internal sac with flagellum or basal sclerite associated with gonopore (e.g., Figs. 58, 59 ); Geraeus Pascoe. ...... 2

– Prosternum with posterior line of anterior tubulate portion lacking enlarged punctures and adjacent longitudinal folds ( Figs. 4–8 ); at least female with vestiture on median line radiating from central point on posterior line of tubulate portion; internal sac without sclerite associated with gonopore; Linogeraeus Casey. .......................................... 11

2. Desmomere 2 elongate, more than 4 times longer than wide; rostrum very slender ( Figs. 10, 14, 16 ); inner margins of mandibles diverging apically... 3

– Desmomere 2 short, at most 3 times longer than wide; rostrum thicker ( Figs. 18, 20, 24 , 26, 28, 30 ); inner margins of mandibles not diverging apically.......................................................................... 5

3. Body slightly stouter ( Figs. 13, 15 ); pronotum with scales oriented towards scutellum in basal half of mid-line; only desmomeres 5–7 with inconspicuous erect setae; in United States widely distributed east of Rocky Mountains........................................ G. penicillus (Herbst)

– Body slightly more elongate ( Figs. 9, 11 ); pronotum with scales oriented towards mid-line except immediately in front of scutellum; desmomeres 2–7 with erect setae; in United States restricted to southern Arizona and western Texas ................................................................... 4

4. Tarsal claws wide, hollowed underneath, apex round; elytra with fasciae of dark scales ( Fig. 9 ); male with prosternal spines. G. euryonyx Champion

– Tarsal claws not noticeably widened; elytra with uniform vestiture ( Fig. 11 ); male without prosternal spines................ G. nimbatus (Casey)

5. Small species, total length less than 3 mm ................................... 6

– Larger species, total length more than 3 mm ................................ 8

6. Anterior tubulate portion of prosternum with longitudinal fold in front of coxa; male with prosternal spines; widely distributed... G. picumnus (Herbst)

– Anterior tubulate portion of prosternum without folds; male without prosternal spines; southern Arizona .......................................... 7

7. Body stout; pronotum proportionately larger ( Fig. 25 ); male with ventrites 1 and 2 shallowly depressed and with normal setae......................................................................... G. minor , new species

– Body elongate; pronotum proportionately smaller ( Fig. 27 ); male with ventrites 1 and 2 deeply depressed and with plumose setae.......................................................................... G. petilior , new species

8. Elytral vestiture heterogeneous, base of interstria 2 with dense cluster of scalloped scales................................................................. 9 – Elytral vestiture homogeneous, base of interstria 2 without dense cluster of scalloped scales............................................................. 10

9. Integument often reddish brown; dorsal vestiture with rather broad, scalloped scales; base of interstriae 1 and 2 with ill-defined patch of scales; elytral disk with few scattered dark scales ( Fig. 17 ); male with ventral depression with some inconspicuous erect hairs.... G. modestus (Boheman)

– Integument black; dorsal vestiture with slender scales; base of interstriae 1 and 2 with well-defined patch of broad, scalloped scales; elytral disk with postscutellar area with patch of dark scales ( Fig. 23 ); male with ventral depression with cushion of long, erect hairs............................................................................... G. patagoniensis (Sleeper)

10. Pronotal disk with punctures separate; dorsal vestiture appressed; male with blunt tubercle on submentum; apex of aedeagus round ( Fig. 58 )............................................................ G. coarctatus Champion

– Pronotal disk with longitudinal ridges; dorsal vestiture suberect; male without tubercle on submentum; apex of aedeagus spatulate ( Fig. 59 ).......................................................... G. pannuceus , new species

11. Size 4.5–5.7 mm; elytra with variously dense vestiture on alternating intervals, appearing striped ( Fig. 41 ); prothorax with anterior tubulate portion distinctly constricted in dorsal view; eyes small, longest diameter less than 1.5X height of rostrum at base........... L. laevirostris (LeConte)

– Size 2.4–4.8 mm; elytral vestiture either uniform or with more or less distinct x-shaped pattern; prothorax with anterior tubulate portion not distinctly constricted in dorsal view; eyes large, longest diameter more than 1.5X height of rostrum at base......................................... 12

12. Desmomere 1 nearly one-half as long as scape ( Fig. 70 )................... 13

– Desmomere 1 much shorter.................................................. 14

13. Dorsal vestiture homogeneous ( Fig. 47 ); male with protibia excavated distally, funicle with long dorsal setae, prosternal spines absent, profemur with basiventral process; female with rostrum abruptly flattened at point of antennal insertion, apex narrower than base ( Fig. 48 )..... L. hospes (Casey)

– Dorsal vestiture heterogeneous, scales varying in size; male with protibia not excavated distally, funicle with setae evenly distributed, prosternal spines peg-like ( Fig. 35 ), profemur without basiventral process; female with rostrum not abruptly flattened, apex wider than base.......................................................................... L. capillatus (LeConte)

14. Dorsal vestiture homogeneous, all scales of approximately same size, color, shape, and density...................................................... 15

– Dorsal vestiture heterogeneous, scales varying in size, color, and shape [ L. neglectus keys both ways]................................................. 22

15. Males: Rostrum dorsally distinctly punctate; ventrites 1 and 2 depressed; three of four species with prosternal spines in front of coxae............. 16

– Females: Rostrum dorsally glabrous, finely punctate; ventrites 1 and 2 convex; prosternal spines absent............................................. 19

16. Rostrum ventrally with conspicuous scales; prothorax nearly as long as wide ( Fig. 53 ); southern Arizona ................ L. squamirostris (Champion)

– Rostrum ventrally without conspicuous scales; prothorax noticeably wider than long; Arizona and elsewhere..................................... 17

17. Prosternum without spines in front of coxae; body on average more elongate ( Figs. 53, 55 ); apex of aedeagus with sides sinuous ( Fig. 63 ); southern United States................................... L. tonsilis (Boheman) – Prosternum with pair of spines in front of coxae; body on average stouter ( Figs. 49, 51 ); apex of aedeagus with sides gradually convergent ( Figs. 61, 62 ); southern, central, and eastern United States........................... 18

18. Prosternal spines of fully developed male much longer than wide ( Figs. 5 , 50 ), directed ventrad and then curved anteriad; rostrum usually distinctly constricted in apical third, dorsomedially impunctate, ventral margin of scrobe not visible from above ( Fig. 64 ); pronotum with sides evenly rounded, often notably bulky; apex of aedeagus round ( Fig. 61 )......................................................................... L. finitimus (Casey)

– Prosternal spines short triangular and directed anteriad ( Fig. 52 ); rostrum slightly constricted in apical third, dorsomedially punctate, ventral margin of scrobe visible from above ( Fig. 66 ); sides of prothorax gradually converging toward middle and then curved inward; apex of aedeagus pointed ( Fig. 62 )............................. L. neglectus (LeConte)

19. Sides of rostrum subparallel, not widened toward apex, ventral margin of scrobe visible from above ( Fig. 67 ); sides of prothorax gradually converging toward middle and then curved inward. L. neglectus (LeConte)

– Sides of rostrum constricted in apical third and then noticeably widened toward apex, ventral margin of scrobe not visible from above ( Fig. 65 ); sides of prothorax evenly rounded........................................... 20

20. Antenna inserted in basal half of rostrum; rostrum abruptly curved at base, apical portion extremely flattened; prothorax nearly as long as wide................................................ L. squamirostris (Champion)

– Antenna inserted near middle of rostrum; rostrum rather evenly curved, apical portion moderately flattened; prothorax noticeably wider than long 21

21. Pronotum bulky ( Fig. 49 ); femora slightly stouter and usually reddish; southern, central, and eastern United States............ L. finitimus (Casey)

– Pronotum proportionately smaller ( Fig. 53 ); femora slightly more slender and usually fuscous; southern United States.......... L. tonsilis (Champion)

22. Pronotal disk and elytra with dark spots standing in sharp contrast to light-colored basic vestiture and forming conspicuous cross at elytral declivity ( Fig. 31 ); length 3.3–4.8 mm; southern Arizona ............................................................................ L. crucifer (Champion)

– Color pattern inconspicuous and fuzzy; other distribution or of smaller size.............................................................................. 23

23. Pronotum large, approximately 0.6X length of elytra ( Fig. 37 ); male with rostrum conspicuously curved in apical one-half ( Fig. 38 ) and with special characters (prosternum with plumose scales, procoxae with dentiform process, Fig. 8 ; protarsi with long hairs)............... L. urbanus (Boheman)

– Pronotum smaller, less than 0.55X length of elytra ( Figs. 39 , 51 ); male with rostrum more evenly curved, without special characters as above.. 24

24. Dorsal vestiture of predominantly dark brown scales and some, usually linearly arranged, light-colored scales ( Figs. 43, 45 ); elytral declivity distinctly vaulted in lateral view ( Fig. 44 ); male with blunt tubercle on submentum and without prosternal spines.... L. appalachensis , new species

– Dorsal vestiture of lighter color than integument; elytral declivity gently sloping in lateral view ( Figs. 40 , 52 ); male without tubercle on submentum and with prosternal spines...................................... 25

25. Fore coxae separated by less than width of rostrum; integument (particularly legs) usually reddish brown; light-colored scales condensed on pronotal flank, behind scutellum, and at base of interstria 3, elytra with some scattered white scales ( Fig. 39 ); female with rostrum indistinctly tapered in lateral view; size 2.4–3.2 mm ... L. perscitus (Herbst)

– Fore coxae separated by more than width of rostrum; integument dark brown; basic vestiture yellowish to grey intermixed with variable portions of inconspicuous dark scales ( Fig. 51 ); female with rostrum apically distinctly tapered in lateral view; size 2.9–4.5 mm ... L. neglectus (LeConte)

Figures

Figs. 1–8. Geraeus and Linogeraeus species, anterior portion of prosternum. 1) G. modestus, male; 2) G. modestus, female; 3) G. picumnus, male; 4) G. picumnus, female; 5) L. finitimus, male; 6) L. finitimus, female; 7) L. laevirostris, male; 8) L. urbanus, male.

Figs. 57–60. Geraeus and Linogeraeus species, aedeagus, dorsal aspect; scale bars

Figs. 9–16. Geraeus species, dorsal and lateral aspects; scale bar 1 mm. 9, 10) G. euryonyx, female; 11, 12) G. nimbatus, female; 13, 14) G. penicillus, male, maculate form; 15, 16) G. penicillus, female, unicolored form.

Figs. 17–24. Geraeus species, dorsal and lateral aspects; scale bar 1 mm. 17, 18) G. modestus, male; 19, 20) G. coarctatus, male; 21, 22) G. pannuceus, male; 23, 24) G. patagoniensis, female.

Figs. 25–32. Geraeus and Linogeraeus species, dorsal and lateral aspects; scale bar 1 mm. 25, 26) G. minor, male; 27, 28) G. petilior, male; 29, 30) G. picumnus, male; 31, 32) L. crucifer, male.

Figs. 41–48. Linogeraeus species, dorsal and lateral aspects; scale bar 1 mm. 41, 42) L. laevirostris, male; 43–45) L. appalachensis, male; 46) L. hospes, male; 47, 48) L. hospes, female.

Figs. 61–70. Geraeus and Linogeraeus species; 61–63, aedeagus, dorsal aspect of apical portion; 64–67, rostrum, dorsal aspect; 68–70, antenna. 61) L. finitimus; 62) L. neglectus; 63) L. tonsilis; 64) L. finitimus, male; 65) L. finitimus, female; 66) L. neglectus, male; 67) L. neglectus, female; 68) G. picumnus, female; 69) G. timidus, female; 70) L. capillatus, female.

Figs. 33–40. Linogeraeus species, dorsal and lateral aspects; scale bar 1 mm. 33, 34) L. capillatus, female; 35) L. capillatus, male; 36) L. urbanus, female; 37, 38) L. urbanus, male; 39, 40) L. perscitus, male.

Figs. 49–56. Linogeraeus species, dorsal and lateral aspects; scale bar 1 mm. 49, 50) L. finitimus, male; 51, 52) L. neglectus, male; 53, 54) L. squamirostris, female (dorsal), male (lateral); 55, 56) L. tonsilis, female, New Mexico, U.S.A.