310 



Leech and Chandler: Coleoptera 



^.METATIBIA 



LOBCO METATARSAL 

 __SECMCMTS 



Fig. 13:9. Laccophilus terminalis, underside of adult to show 

 episternum of metathorax cut off from middle coxal cavity by 

 mesosternal epimeron (Leech, 1948). 



12. A diagonal - carina crossing epipleura near base (fig. 

 13:13a); front and middle tarsi 4-segmented 



Nygrotus Stephens 1828 



— No carina crossing epipleura; front and middle tarsi 

 actually 5-segmented, though 4th is usually very 

 small and hidden between lobes of 3rd 13 



13. Hind margin of hind coxal processes (best viewed 

 with head of insect toward observer) together virtually 

 straight across (fig. 13:7i) or sinuate and angularly 

 prominent at middle (fig. 13:7;'), or obtusely angulate 

 (fig. 13:7A;), but never triangularly incised at middle; 

 median line of processes thus as long as or longer 

 than lateral coxal lines 14 



— Hind margins of hind coxal processes slightly, to 

 deeply and more or less triangularly incised at middle, 

 median line thus shorter than lateral coxal lines 

 -16 



14. Hind margins of hind coxal processes together either 

 truncate or angularly prominent (fig. 13:7i, k) ...... . 



(in part) Hydroporus Clairville 1806 



— Hind margins of hind coxal processes conjointly 

 sinuate and somewhat angularly prominent at middle 

 (fig. 13:7;-) 15 



15. Hind angles of pronotum rectangular or obtuse 



(in part) Hydroporus Clairville 1806 



— Hind angles of pronotum acute 



(in part) Deronectes Sharp 1882 



16. Pronotum with a longitudinally impressed line or 

 crease on each side, and usually with a shallow 

 transverse impression near base or an impression on 

 each side near base; hind femora with median line of 

 setigerous punctures, otherwise sparsely punctate or 

 nearly smooth; undersurface of body densely finely 

 punctate or shagreened, with scattered or numerous 

 coarser punctures Oreodytes Seidlitz 1886 



— Pronotum without sublateral impressed lines, usually 

 without basal impression; hind femora usually densely 



punctate over entire surface; undersurface of body 

 densely finely punctate to subgranulated, usually 

 lacking scattered large punctures (figs. 13:15a, b; 

 13:16a, b) (in part) Deronectes Sharp 1882 



17. Scutellum covered by hind margin of pronotum, or 

 rarely a small tip visible; hind tarsi each with a 

 single straight claw (fig. 13:9) 18 



— Scutellum entirely visible (fig. 13:76) 19 



18. Spines of hind tibiae notched or bifid at tip; apical 

 3rd of prosternal process lanceolate, only moderately 

 broad (figs. 13:8a, 13:9); larger species, 2.5 to 6.5 mm. 

 long Laccophilus Leach 1817 



— Spines of hind tibiae simple, acute at tip; apical 

 3rd of prosternal process somewhat diamond-shaped, 

 dilated behind front coxae and with tip acute 



Laccodytes Regimbart 1895 



19. Eyes emarginate above bases of antennae (fig. 13:7/); 

 first 3 segments of front tarsi of male widened and 

 with adhesion discs (fig. 13:72) or not, but never 

 together forming a nearly round plate. COLYMBETINAE 



20 



— Eyes not emarginate above bases of antennae (fig. 

 13:7c); first 3 segments of front tarsi of male greatly 

 broadened, forming a nearly round (fig. 13:7tf) or an 

 oval (fig. 13:10a) plate with adhesion discs. DYTIS- 

 CINAE 32 



20. Hind femora with a linear group of ciliae near posterior 

 apical angle (fig. 13:106). AGABINI 21 



— Hind femora without such a group of ciliae 25 



21. Hind coxal processes in form of rounded lobes (fig. 

 13:10a") 22 



— Hind coxal processes parallel-sided, lateral margins 

 straight to apices (fig. 13:10e) 



Agabinus Crotch 1873 



22. Hind tarsal claws of equal length; if slightly unequal, 

 then both are very short, only 1/3 length of 5th tarsal 

 segment 23 



— Hind tarsal claws obviously unequal, outer one of 

 each pair 2/3 or less length of inner claw (fig. 13:10/) 



24 



23. Labial palpi very short, terminal segments subquadrate 

 (fig. 13:10a) Hydrotrupes Sharp 1882 



— Labial palpi approximately as long as maxillary palpi, 

 terminal segments linear, not subquadrate (fig. 13:10A) 



Agabus Leach 1817 



24. Labial palpi with penultimate segments enlarged, 

 triangular in cross section, the faces concave and 

 unequal (fig. 13:10i); genital valves of female dorso- 

 ventrally flattened, not armed with teeth 



Carrhydrus Fall 1922 



— Labial palpi with penultimate segments linear, not 

 enlarged and triangular; genital valves of female 

 laterally compressed, sawlike, with series of sharp 

 teeth along upper edge (fig. 13:10c) 



flybius Erichson 1832 



25. Prosternum with a median longitudinal furrow, from 

 near front margin to apex of prosternal process; first 

 4 hind tarsal segments distinctly produced at upper 

 (inner) posterior corners. MATINI 



Matus Aube 1836 



— Prosternum without a median longitudinal furrow; 

 hind tarsal segments not lobate at upper hind corners 



26 



26. Hind coxal lines divergent anteriorly, coming so close 

 together posteriorly as almost to touch median line, 

 thence turning outward almost at right angles onto 

 hind coxal processes (fig. 13:10&); hind tarsal claws 

 equal; pronotum clearly but narrowly margined laterally. 

 COPELATINI Copelatus Erichson 1832 



— Hind coxal lines never almost touching median line 

 and thence turning outward almost at right angles 

 onto coxal processes; hind tarsal claws equal or not; 

 pronotum margined or not 27 



27. Hind claws of same length or virtually so; smaller 

 species, 6 to 9 mm. long 28 



— Hind claws obviously unequal, outer ones only from 

 1/3 to 2/3 length of inner ones; larger species, 9 to 20 



