Formicomus pedestris

Hemp, Claudia & Dettner, Konrad, 2003, Description of Larvae of the Genus Formicomus Laferté, and Data on the Life Cycles of Omonadus floralis (Linné) and Notoxus monoceros (Linné) (Coleoptera: Anthicidae), The Coleopterists Bulletin 57 (4), pp. 361-368 : 362

Description of the First Instar Larva of Formicomus pedestris

Average body length approximately 1 mm; average width of body at metathorax approximately 0.25 mm.

EPIPHARYNX ( Fig. 1a dorsal view; 1b ventral view) twice as broad as long; 2 pairs of dorsal setae, one pair central, the other posterad; two pairs of lateral setae, a short pair at apex; ventrally at the anterior margin a pair of conical spines; several small spines in semicircular rows ventrally in the centre of the epipharynx.

MANDIBLE ( Fig. 2 dorsal view) with 2 setae on the dorsolateral edge; several setae clustered adjacent to base of mola (penicillus); left and right mandible with toothed molar area.

LABIUM ( Fig. 3a dorsal view; 3b ventral view) with 2 pairs of ventral setae, 1 at base of palpi, 1 at base of labium; numerous setae at dorsal side of ligula; several finger-like projections with prominent central one at apex of segment 2 of labial palpi.

MAXILLA ( Fig. 4 ventral view) with long and short seta on outer edge, 2 setae ventrad; mala rounded, with 15 spines (5 at apex, followed by a lateral row of 4 spines and two parallel rows of 3 spines each). Maxillary palpus with 2 setae on segment 2, one dorsal at the margin the other ventrally in the middle of segment 2 placed; apex of segment 3 with numerous finger-like projections.

ANTENNA ( Fig. 5 dorsal view) about ¼ width of head; segment 1 slightly / shorter and wider than segment 2, segment 3 nearly 4 x length of segment 2, width about 1 3; sensory appendix 2–3 times broader and longer than segment 3. /

PROTHORACIC LEG ( Fig. 6 ventral view) with large circular / coxa, 1 3 wider than trochanter; tibiotarsus and femur almost same length; claw approximately 2 3 length of tibiotarsus.

UROGOMPHI ( Fig. 7 dorsal view) forming an acute emargination at base, no chalazae on inner margin, prominent lateral chalazae (setae 5 times longer than apices of urogomphi); large dorsal, smaller ventral and a pair of short setae laterad below apex.

HEAD CAPSULE ( Fig. 8a ventral view; 8b dorsal view). Lacking epicranial and frontoclypeal sutures; one pair of stemmata near base of antennae; ecdysial cleavage line forming a lyre-shaped figure enclosing front; head quadrate, prognathous; clypeus and labrum indistinct; ventrally /: two setae at base of antenna, another two further centrad; maxillar region about ½ width and 2 3 length of head; at base of maxillae two elongated structures.

The differences found in the first instar larvae of F. gestroi and F. rubricollis are small ( Figs. 9–11 ). The sensory appendix of F. rubricollis ( Fig. 12 ) is distinctly shorter than segment 3, whereas the antenna of F. gestroi ( Fig. 13 ) shows no significant difference from that of F. pedestris ( Fig. 15 ). The urogomphi ( Fig. 14 , F. gestroi ) are similarly shaped in all three Formicomus species.

Figures

Figs. 1–7. Formicomus pedestris, first instar larva. 1) Epipharynx, dorsal (a) and ventral (b) view; 2) mandibles, dorsal view; 3) labium, dorsal (a) and ventral (b) view; 4) maxillae, ventral view; 5) antenna, dorsal view; 6) prothoracic leg, ventral view; 7) urogomphi, dorsal view.

Fig. 8. Formicomus pedestris. First instar larva. Head capsule, ventral (a) and dorsal (b) view.

Figs. 9–22. Formicomus ssp., Omonadus floralis and Notoxus monoceros. Scanning electron micrographs of larvae. 9) Formicomus rubricollis, ventral view of the head (3433); 10) F. gestroi, ventral view of the head (3623); 11) F. pedestris, ventral view of the head (3963); 12) F. rubricollis, antenna, ventral view (1,5103); 13) F. gestroi, antenna, ventral view (9193); 14) F. gestroi, urogomphi, ventral view (4973); 15) F. pedestris, antenna, ventral view (1,4603); 16) Omonadus floralis, ventral view of the head (1103); 17) Notoxus monoceros, dorsal view of the head (1443); 18) N. monoceros, ventral view of the head (1583); 19) O. floralis, antenna, ventral view (6363); 20) O. floralis, urogomphi, dorsal view (1113); 21) N. monoceros, antenna, dorsal view (6003); 22) N. monoceros, urogomphi, lateral view (1263).