Key to the Lasius of the Indian Himalayas

This worker key is based on Bharti, H.; Gul, I. 2013. Lasius elevatus, a new ant species of the subgenus Cautolasius (Hymenoptera: Formicidae) from the Indian Himalayas. Asian Myrmecology 5:53-58.

1

Eyes small, eye length one-sixth or less the length of lateral cephalic margin; colour yellow to yellowish brown . . . . . 2
Eyes larger, eye length more than one-fifth the length of lateral cephalic margin; colour pale brown to black . . . . . 7

2

return to couplet #1

Gena curving inwards below eyes to close-set mandibular insertions; petiole low and thick, subconical in side view with rounded dorsal crest; queen exceedingly small (HW 760-790 μm) . . . . . Lasius carniolicus

Head of Lasius carniolicus worker

Profile of Lasius carniolicus worker

Genal margins straight or curving gently to wide-set mandibular insertions; petiole tapering dorsally in side view; queen larger in size (HW > 790 μm) . . . . . 3

3

return to couplet #2

Petiole, in frontal view, with deeply emarginate dorsal crest . . . . . Lasius bicornis

Head of Lasius bicornis worker

Profile of Lasius bicornis worker

Petiole, in frontal view, with unbroken dorsal crest or with shallow emargination . . . . . 4

4

return to couplet #3

Large species; head width 950-1250 μm . . . . . 5
smaller species; head width 670-860 μm . . . . . 6

5

return to couplet #4

Petiole in front view high, conical, tapering to narrow rounded dorsal crest . . . . . Lasius mikir

Head of Lasius mikir worker

Profile of Lasius mikir worker

Petiole in front view, with broadly rounded sides, dorsal crest convex, occasionally with slight median incision; petiole and basal face of gaster with very long curved hairs; tibiae without projecting hairs; occipital hairs restricted to median area . . . . . Lasius crinitus

Head of Lasius crinitus worker

Profile of Lasius crinitus worker

6

return to couplet #4

Petiole node in frontal view with feebly convex sides, narrowing towards the crest and somewhat rounded dorsal crest; eye smaller (EL <90 μm) . . . . . Lasius elevatus

Head of Lasius elevatus worker

Profile of Lasius elevatus worker

Petiole in frontal view with sides not narrowing towards the crest and a straight dorsal crest; eye larger (EL>120 μm) . . . . . Lasius alienoflavus

Head of Lasius alienoflavus worker

Profile of Lasius alienoflavus worker

7

return to couplet #1

Combined total number of hairs on hind tibia plus hairs on scape not exceeding 8 . . . . . 8
Combined total number of hairs on hind tibia plus hairs on scape always greater than 8 . . . . . 11

8

return to couplet #7

Dorsum of scape with perfectly appressed pubescence; masticatory margin of mandibles usually with 7 or fewer teeth; pubescence on all surfaces of body perfectly appressed or decumbent, giving smooth appearance . . . . . 9
Dorsum of scape with pubescence hairs projecting ≤ 5 μm from cuticular surface; masticatory margin of mandibles usually with 8 or more teeth; pubescence on surface of body not perfectly appressed or decumbent, therefore rough in appearance . . . . . 10

9

return to couplet #8

Size smaller; head and mesosoma yellowish brown to pale brown, gaster dark brown; SL/HL <0.86; CI<104 . . . . . Lasius brunneus

Head of Lasius brunneus worker

Profile of Lasius brunneus worker

Size larger; head, mesosoma and gaster brown to dark brown; SL/HL >0.87; CI>104 . . . . . Lasius himalayanus

Head of Lasius himalayanus worker

Profile of Lasius himalayanus worker

10

return to couplet #8

Scape shorter, SL/HL < 0.890; mesopropodeal depression deep, mesonotum high and vaulted; mesosoma yellowish brown . . . . . Lasius breviscapus

Head of Lasius breviscapus worker

Profile of Lasius breviscapus worker

Scape longer, SL/HL > 0.890; mesopropodeal depression shallow; the propodeal dome is more conical; the species is relatively concolorous, with the mesosoma dirty brown . . . . . Lasius alienus

Head of Lasius alienus worker

Profile of Lasius alienus worker

11

return to couplet #7

Paramedian pubescence hairs on posterior dorsum of gastral tergites directed caudomedially or medially; clypeal pubescence extremely sparse (PDCL > 30); broad and massive petiolar scale . . . . . Lasius magnus

Head of Lasius magnus worker

Profile of Lasius magnus worker

Pubescence hairs on whole surface of gastral tergites directed strictly longitudinally; clypeal pubescence much denser (PDCL < 30); petiolar scale comparatively smaller . . . . . 12

12

return to couplet #11

PDCL < 18; propodeal dome high and hemispheric to conic-hemispheric; posteroventral sides of pronotum more-or-less pubescent, somewhat dull; colour of head and gaster blackish brown, mesosoma dark brown to medium brown . . . . . Lasius niger

Head of Lasius niger worker

Profile of Lasius niger worker

PDCL > 18; propodeal dome flatter; posteroventral sides of pronotum without pubescence, brilliantly shining; whole body concolorous yellowish to reddish brown . . . . . Lasius wittmeri

Head of Lasius wittmeri worker

Profile of Lasius wittmeri worker