Occipital carina complete; eyes convergent in frontal view, face maximum width 1.7 × minimum width; mandibles moderately twisted; notauli deeply impressed, distinctive and foveolate; propodeum carinate-rugose, with a transversal carina; hind coxa rugose; tarsal claw with a large lobe; dorsope present, very small; ventral borders of first tergite widely separated; ovipositor thickened basally and slightly curved; ovipositor 3.1 × longer than first tergite.

Antenna brown; annulus absent; head yellow except area between ocelli dark brown. Anterior half of propleuron dark brown, posterior half light brown; pronotum yellow; median mesonotal lobe and scutellum yellow, lateral mesonotal lobes light brown; mesopleuron laterally yellow, ventrally light brown; metanotum black dorsally, yellow laterally; metapleuron yellow; propodeum black. Prothoracic legs yellow; mesothoracic coxa, trochanter and trochantellus white, remaining leg dark brown; metathoracic legs yellow except tarsus light brown. T1 black; T2–T8 and sterna yellow. Wings hyaline; stigma white.

2.8 mm.

Antenna with 22 flagellomeres; head 1.2 wider than high; occipital carina complete; ocellus-ocullar distance 2 × ocellar diameter; head height 1.5 × eye height; temple length 0.5 × eye length in dorsal view; vertex in dorsal view not descending vertically behind the lateral ocelli; frons strigulate; face maximum width 1.7 × minimum width; face puncticulate; face minimum width 0.7 × clypeus width; clypeus smooth and polished; malar space length 0.5 × mandible width basally; mandibles moderately twisted.

Surface of pronotum in lateral view irregular and shiny; propleuron mostly smooth except anteriorly rugulose; notauli deeply impressed, distinctive and foveolate; mesonotal lobes well defined; central lobe of mesoscutum with irregular punctures and polished; scutellar furrow with one carina; mesopleuron with irregular punctures; precoxal sulcus short, narrow and foveate; metapleuron with irregular punctures; propodeum carinate-rugose, with a transversal carina.

Hind coxa rugose; tarsal claw with a large lobe.

Wing length 2.9 mm; second submarginal cell of forewing not strongly narrowed anteriorly. Front wing: length of vein r 0.9 × length of vein 3RSa; vein 3RSb straight; length of vein 3RSa 0.6 × length of vein r-m; vein m-cu antefurcal. Hind wing: length of vein 1M 1.6 × length of vein cu-a; length of vein 1M 1.2 × length of vein r-m.

Dorsope present, very small; ventral borders of first tergite widely separated; first tergite costate-rugulose; ovipositor thickened basally and slightly curved; ovipositor 3.1 × longer than first tergite; T2–T3 with irregular and shiny surface.

Unknown.

Unknown.

Unknown.

COSTA RICA, Cartago, Cerro de la Muerte, Villa Mills, 3000 m.

Holotype female (point mounted), COSTA RICA, Cartago, Cerro de la Muerte, Villa Mills, 3000 m, collected XI–XII.1989, P. Hanson leg., UWIM.

Paratype. Unknown.

Costa Rica, province of Cartago.

Unknown.

Compared with Meteorus fallacavus, Meteorus microcavus displays a true pair of dorsopes but too small to be detected at a first glance. The ventral borders being widely separated support this interpretation. It is unusual to find such a reduction in these structures, so the conspicuous dorsopes diminution in Meteorus microcavus might be enough to identify it. Meteorus andreae, a common species distributed across the montane forests of Colombia and Costa Rica, matches with Meteorus fallacavus by sharing the following features: moderately twisted mandibles, propodeum having carinae, presence of true dorsopes, ventral borders of fist tergite widely separated. However, Meteorus microcavus differs by its mesopleuron mostly yellow (mesopleuron completely black in Meteorus andreae), antenna with 22 flagellomeres (antenna with 27–32 flagellomeres in Meteorus andreae) and tarsal claw with a large lobe (tarsal claw either simple or with a small lobe in Meteorus andreae).

The specific epithet is composed by the Greek prefix “micro” meaning small, and the Latin stem “cavus”, which means hole, referring to the small dorsopes.