From the original description and corresponding key to similar species (Papp 1987).
Characters used in the key. First tergite relatively little (Figs 157, 228), evenly broadening posteriorly, either somewhat longer than or as long as borad behind; second tergite transverse, 2.1-2.3 times wider behind than long medially (Figs 157, 228), rugulose with longitudinal elements. Temple in dorsal view somewhat more rounded, eye about 1.3-1.4 times as long as temple (Fig. 155). Hind tarsal joints relatively long, basitarsus only twice longer than second joint (Fig. 158). Mesonotum glistening with disperse and rather fine punctation, notaulix distinct by fine rugulosity. Pterostigma issuing radial vein less distally from its middle (Fig. 159). Legs rather yellow. Pterostigma rather opaque light brown with a faint yellowish basal spot. Females and males: 3 mm. Mesonotum glistening, with disperse and rather fine punctation, notaulix distinct by fine and dense rugulosity. Maxillar palp 6-jointed as usually. Third tergite polished. Head in dorsal view 1.9 times as broad as long (Fig. 155). Discoidal cell slightly wider than high (Fig. 159). Hypopygium strong, behind truncate (Fig. 154). Fifth joint of fore tarsus without spinule. Along median vein of fore wing both median and submedian cells evenly setose as elsewhere on wing. Second tergite rugulose with longitudinal elements.
Original description. Female. Body 2.9-3 mm. Head in dorsal view (Fig. 155) transverse, 1.8-1.9 times as broad as long, eye about one-third as long as temple latter rounded. Eye in lateral view twice as high as wide, its width more or less greater than width of temple. Ocelli on a low triangle, distance between fore and a hind ocelli either as long as diameter of an ocellus (Fig. 155), or latter slightly greater. Face about one-third wider than high, inner margin of eye subparallel. Clypeus about 2.5 times wider below than high medially. Malar space somewhat longer than basal width of mandible. Head shiny, face almost smooth, frons f vertex polished. Antenna about as long as body, first flagellar joint 2.5-3 times as long as broad, further joints gradually shortening so that penultimate joint twice as long as broad. Mesosoma in lateral view 1.4(-1.5) times as long as high, in dorsal view about as broad between tegulae as breadth of head. Mesonotum shiny with fine punctation, notaulix indicated by somewhat crowded punctation-frugulo-subrugulosity on interspaces, interspaces of mesonotum rather greater than diameter of punctures. Scutellum polished. Propodeum rugose with scrobiculate elements, with a less conspicuous medio-longitudinal keell. Mesopleuron above and anteriorly punctate-sub-punctate, otherwise polished. Hind femur (Fig. 156) 3.8-4 times as long as broad. Hind tarsus about one-fourth longer than hind tibia. Hind basitarsus twice as long as second tarsal joint (Fig. 158). Fore wing about as long as body. Pterostigma (Fig. 159) 2.5-2.7 times as long as wide, issuing radial vein distally from its middle; metacarp either as long as pterostigma or slightly shorter, metacarp about thrice longer than distance between its distal end and tip of radial vein; rl as long as cuqul or slightly shorter. Discoidal cell slightly wider than high, d2 usually twice as long as dl or, less usually, somewhat shorter. Nervellus straight to almost straight. Metasoma as long as mesosoma and distinctly shorter than mesosoma and head together. First tergite either somewhat longer than wide behind (Fig. 157), or about as long as wide (Fig. 228); second tergite 2.3-2.4 times wider behind than long medially and distinctly shorter than third tergite (Fig. 157). First tergite rugose, posteriorly roughly rugose; second tergite rather longitudinally rugo-rugulose; further tergites polished; setae of third tergite restricted behind in a row (similar to that of A. glomeratus). Hypopygium in lateral view (Fig. 154) medium sized, slightly S-like truncate; ovipositor sheath about as long as fourth joint of hind tarsus. Body black. Clypeus and oral part dark brown to brownish, palpi yellow. Mandible brown. Tegula brown. Legs yellow, coxae 1-2 brownish black, coxa 3 black. Tip of hind femur darkening. Tarsal joints brownish fumous. Wings hyaline, pterostigma brownish to light brownish with a rather effaced pale basal spot, r1+cuqu1 light brownish to yellowish brownish, other veins pale pigmented.
Male. Similar to female. Antenna somewhat longer than body, flagellar joints not shortening distally, i.e. every joint 2.5-3 times as long as broad. First tergite longer than broad behind (Fig. 157).
The species is closely related to Cotesia glomerata (L.) and C. berberis (Nixon).