MOLYTINAE, Schonherr, 1823

Balalaikins, Maksims & Bukejs, Andris, 2012, Latvian Molytinae (Coleoptera, Curculionidae): Research History, Fauna And Bionomy, Acta Biologica Universitatis Daugavpiliensis 12 (3), pp. 2-20 : 12-15

AN ILLUSTRATED KEY TO THE LATVIAN MOLYTINAE

1 (4) Onychium reduced, claws inserted to 3rd tarsal segment ( Fig. 20 ).

2(3) Elytral intervals without pale semierect scales, with fine subrecumbent setae. Black, only scape redish. B ody length 1.6–2.0 mm. Habitus ( Fig. 14 ).................................. Anoplus plantaris

3(2) Elytral intervals with single row of short (not longer than half of interval width) pale semierect scales, fine subrecumbent setae indistinct. Black, only scape redish. Body length 1.9–2.5 mm. Habitus ( Fig. 13 ) ……………...….. Anoplus roboris 4(1) Onychium normally developed ( Fig. 21 ).

5(20) A ntennae inserted towards the apex of the rostrum ( Fig. 18 ).

6(9) Elytra without humeral tubercles.

7(8) Femora without denticles. Humeri not prominent anteriorly, rounded. Base of pronotum distinctly narrower than base of elytra. Dorsum with spots of yellowish-gray scales: pronotum with lateral longitudinal spots; elytra with irregularly located little spots. Black, sometime with bluish reflex. Body lenght 14.3-21.0 mm. Habitus ( Fig. 1 ) ................................ Liparus glabrirostris

8(7) Femora with large denticle. Humeri prominent anteriorly. Base of pronotum approximately as wide as base of elytra. Base of pronotum with dense yellowish scales; elytra usually without spots of scales. Black, shining. Body lenght 8-15 mm. Habitus ( Fig. 2 ).............. Liparus coronatus

9(6) Elytra with distinct humeral tubercles.

10(13) External surface of mandibles with dense long setae ( Fig. 23 ).

11(12) Lateral sides of pronotum with distinct longitudinal bands of pale scales. Lateral sides of abdomen with spots of light scales. Denticle of profemora minute, acute, sometime indistinct. Legs slender. Pronotum almost conically narrowed anteriorly; lateral sides weekly rounded. Dorsum covered with with and pale redish-brown; elytra with 4 spots of white scales: 2 on disc and 2 in apical 1/3. Body length 7–13 mm. Habitus ( Fig. 6 ) ....................... Lepyrus palustris

12(11) Lateral sides of pronotum without distinct longitudinal bands of pale scales. Abdomen without spots, uniformly covered with hair-like scales. Denticle of profemora large, obtuse, widely rounded. Legs robust. Pronotum shorter, lateral sides distinctly rounded. Dorsum covered with whit and pale brown scales; elytra with 2 white in apical 1/3. Body length 8–12 mm. Habitus ( Fig. 7 )............................................ Lepyrus capucinus

13(10) External surface of mandibles without setae ( Fig. 22 ).

14(15) Discal part of pronotum with distinct impression in the middle and short convex carina along the median line. Scutellum smooth, shiny, hairless. All femora without denticles, only with little angular prominency. Black. Elytra with small spots of yellowish hair-like scales. Body length 12.0–17.0 mm. Habitus ( Fig. 4 ). ……… …...............................…… Hylobius excavatus

15(14) Discal part of pronotum uniformly convex, without distinct impression. Scutellum punctured, with pubescence (sometime indistinct).All femora distinctly dentate. Elytra with more or less distinct bands or transverse spots of yellowish hair-like scales.

16(17) Lateral sides of metathorax smooth and shiny. Funiculus slender ( Fig. 24 ). Pronotum with large, coarse punctures, interspaces between them shiny and coarsely rugose. Rusty-red to redish-brown. Body length 7.5- 11 mm. Habitus ( Fig. 8 ).................... Hylobius transversovittatus

17(16) Lateral sides of metathorax punctured. Funiculus comparatively more robust ( Fig. 25, 26 ). Body colouration varies from almost black to reddish-brown.

18(19) Pronotum with relatively fine, deep and dense punctures, interspaces between them partly transversely rugose. Punctures in elytral striae equal and relatively fine from base to apex, intervals wider than striae. Lateral sides of abdomen with spots of light scales.Almost black to brown. Body length 7.3-13.5 mm. Habitus ( Fig. 3 )........... .................................................... Hylobius abietis

19(18) Pronotum with larger, shallow punctures, interspaces between them not rugose. Abdomen without spots, uniformly covered with hair-like scales. Punctures in elytral striae unequal: in basal and discal parts larger, in apical part finer.Almost black to reddish-brown. Body length 6.1-9.5 mm. Habitus ( Fig. 5 )......................... Hylobius pinastri

20(5) Antennae inserted near the middle of the rostrum ( Fig. 19 ).

21(22) All femora dentate. Dorsum with recumbent scales and erect rounded scales; on pronotum erect scales form longitudinal rows, on elytra they located on odd intervals. Brown, antennae and tarsi rufous. Elytra behinde the middle with pale band. Smaller, body length 2.5-3.9 mm. Habitus ( Fig. 15 ). ............................... Trachodes hispidus

22(21) All femora edentate. Dorsum only with recumbent scales. Larger, body length not less than 4 mm.

23(26) Posterior angles of pronotum weak, rounded ( Figs 30, 32 ).

24(25) Elytra with two bands of yellowish scales. Pronotum in basal part with V-shaped flattened impression. Elytral intervals 3 and 5 weakly convex. Dark brown to black. Body length 5.0-6.5 mm. Habitus ( Fig. 12 )..…….. Pissodes harcyniae

25(24) Elytra with one transverse large spot of yellowish-rufous scales near the middle. Pronotum at the base with little fovea. Rufous to reddish-brown. Body length 4.0-5.3 mm. Habitus ( Fig. 16 )................................. Pissodes piniphilus

26(23) Posterior angles of pronotum distinct (27, 28, 29, 31).

27(30) Anterior angles of pronotum acute ( Fig. 27, 29 ).

28(29) Punctures in elytral striae distinctly unequal: fovea-shaped, large and fine. Elytra behinde the middle with whide transverse band of yellowish-brown scales. Dark reddish-brown. Body length 5-10 mm. Habitus ( Fig. 9 )................. .................................................... Pissodes piceae

29(28) Punctures in elytral striae almost homogenous, relatively fine and dense. Elytra with two bands of scales: one unicolour rufous in basal 1/3; second bicoloured (white at suture and rufous at the sides) behind the middle. Reddish-brown. Body length 4.5-7.2 mm. Habitus ( Fig. 11 )........ ............................................... Pissodes castaneus

30(27) Anterior angles of pronotum obtuse or rectangular ( Figs 28, 31 ).

31(32) Punctures in elytral striae small, shallow, narrow. Elytra with two bands of pale scales: one in basal 1/3; second distinctly bicoloured (white at suture and rufous at the sides) behind the middle. Rufous-brown, rostrum, funiculus and tarsi black. Body length 4.3-6.3 mm. Habitus ( Fig. 17 ). ……………………… Pissodes validirostris

32(31) Punctures in elytral striae coarse, deep, quadrangular. Elytra with two bands of yellowish or rufous scales. Dark brown or rusty-brown (in immature specimens). Body length 5.1-9.2 mm. Habitus ( Fig. 10 ). ……................... Pissodes pini

Figures

Fig. 18–26. Molytinae: 18 - Hylobius transversovittatus, rostrum and antennae, 19 – Pissodes harcyniae, rostrum and antennae, 20 – Anoplus sp., protarsus, 21 – Hylobius sp., protarsus, 22 – Hylobius abietis, apex of rostrum, dorsal view, 23 – Lepyrus palustris, apex of rostrum, dorsal view, 24 – Hylobius transversovittatus, antenna, 25 – Hylobius pinastri, antenna, 26 – Hylobius abietis, antenna.

Fig. 9–17. Molytinae, habitus, dorsal view: 9 – Pissodes piceae (after Borowiec 2007), 10 – P. pini, 11 – P. castaneus, 12 – P. harcyniae, 13 – Anoplus roboris, 14 – Anoplus plantaris, 15 – Trachodes hispidus, 16 – Pissodes piniphilus, 17 – P. validirostris.

Fig. 1–8. Molytinae, habitus, dorsal view: 1 – Liparus glabrirostris, 2 – L. coronatus, 3 – Hylobius abietis, 4 – H. excavatus, 5 – H. pinastri, 6 – Lepyrus palustris, 7 – L. capucinus, 8 – Hylobius transversovittatus.

Fig. 27–32. Pronotum, dorsal view: 27 – Pissodes piceae, 28 – P. pini, 29 – P. castaneus, 30 – P. harcyniae, 31 – P. validirostris, 32 – P. piniphilus.