Bibio

Skartveit, John, 2010, The larvae of European Bibioninae (Diptera, Bibionidae), Journal of Natural History 36 (4), pp. 449-485 : 471

Bibio ru®pes ( Zetterstedt, 1838) (®gures 61 ±67)

Larva not previously described. Brownish white, dull.

Head. Head capsule widths ®rst instar 0.23±0.25 mm (n = 31), third instar 0.35 ± 0.43 mm (n = 38), fourth instar 0.45±0.61 mm (n = 349), ®fth instar 0.64±0.84 mm (n = 248), sixth instar 0.86 to ca 1.15 mm (n = 362), seventh instar ca 1.15±1.52 mm (n = 172).

Labrum (®gure 61) with one pair of long setae on transverse carina. Mandible (®gure 62) with ®ve teeth. Maxilla (®gure 63) with one strong and three or four smaller mesal teeth, laterally with four or ®ve short and blunt teeth, with 8±10 round`holes’ on inner surface. Prementum (®gure 63) with prominent anterior corners, eight sensillae. Stemmata present at least in some specimens. Antenna diameter ca 40 m m with approximately six slender sensillae.

Body. Dorsal processes clearly arranged in three pairs, mesal pair slightly shorter than lateral pairs. Post-spiracular processes twice as long as spiracle diameter, situated two spiracle diameters posterior to spiracle. Cuticle: prothorax (®gure 64) anterior part with larger scales oval, slightly irregular but smooth in outline, 30±50 m m wide, each with 5±12 spines as long as or slightly longer than scales. A few smaller scales in between the larger ones on prothorax, further back approximately two smaller, spineless scales for each larger, spine-bearing. Transverse bands without spine-bearing scales rather wide. Towards the rear spines progressively fewer, metathorax (®gure 65) each larger scale with three to six spines, on ®rst abdominal with one to ®ve spines, on second abdominal with one to three spines, on third and fourth (®gure 66) abdominal with one to three spines (few with more than two), from ®fth abdominal segment backwards almost exclusively with one spine on each scale. Spines ca 20 m m long, conical, clearly more pointed than in B. brunnipes . Ninth abdominal segment (®gure 67) spines reduced to pegs, scales very close-packed and slightly overlapping. Venter of ninth abdominal segment with scales bearing slender spines, spines much longer and less dense than in B. brunnipes . Spiracles protruding approximately one-half spiracle diameter.

Distribution. Holarctic. Scandinavia, British Columbia to Colorado ( Fitzgerald and Skartveit, 1997).

Ecology. Wet and dry meadows, mires. Seems to be especially fond of wet habitats. Two-year life cycle (Skartveit and Solhùy, 1997).

Material. Norway, STI: Oppdal , Sùre Knutshù 1150 m a.s.l., edge of mire, J. Skartveit leg., 56 larvae; HOI: Eidfjord , 1.1 km SSE Stistuv tourist hut, dry meadow 1275 m a.s.l., T. Solhùy leg., 2885 larvae ; 1.4 km SE Stigstuv tourist hut wet, meadow 1325 m a.s.l., T. Solhùy leg., 7 larvae (all in ZMUB) .