Adelius nigripectus Muesebeck, 1922

Shimbori, Eduardo M., Bortoni, Marco A., Shaw, Scott R., Souza-Gessner, Carolina Da S., Cerântola, Paula De C. M. & Penteado-Dias, Angélica M., 2019, Revision of the New World genera Adelius Haliday and Paradelius de Saeger (Hymenoptera: Braconidae: Cheloninae: Adeliini), Zootaxa 4571 (2), pp. 151-200 : 182-184

Adelius nigripectus Muesebeck, 1922

( Figs 86–91 )

Adelius nigripectus, Muesebeck 1922: 13

Type material examined. Holotype , ♂: labels top to bottom: 1. “Cage C1269b”; 2. “Lafayette Ind. IX.?”; 3. “Issued IX.24.15”; 4. “Reared from Car. Poplar Leaf Miner”; 5. “ Acoelius det. Gahan ”; 6. “Type No. 23951 U.S. N.M.”; 7. “ Acoelius nigripectus Mues. Type ♂ ”. Type locality: Lafayette, Indiana, USA. Type in fairly good condition, both antennae broken at pedicel. Non-type material examined: ♀, USA: Kansas, Riley Co., Konza Praire Biological Station , N 2B, 39°05’27” N 96°35’09” W, Malaise trap, 24.VII–31.VII.2001, Zolnerowich, Kula & Brown (UKHI)

Description of ♀. Body length: 1.9 mm; fore wing length: 1.53 mm.

Color. Yellow. Mesoscutellar trough posteriorly and posterior bar, metanotum and metasoma apically brown; metasoma lighter at base. Legs yellow, hind tarsi dark brown; hind femur and tibia with some darker indistinct stains; tarsomere 5 of fore and mid legs dark brown. Palpi whitish yellow. Antenna dark brown with first 4–5 segments light yellow. Wings with two faint infuscate bands, the apical one stronger just below stigma and the basal one weaker than apical but stronger at 1st subdiscal cell; veins and stigma pale brown.

Head. Face very weakly granulate-rugulose above, most of head smooth and polished with few weak striations at vertex and frons near stemmaticum. Frons distinctly excavated. Temples directly receding behind eyes. Antennae about as long as body; mid segments expanded ventrally, almost as long as wide to weakly longer. Head 0.53× longer than wide in dorsal view. Scape 2.2× longer than wide. Eye height 4.5times longer than malar space.

Mesosoma. Mesoscutum punctate anteriorly, posteriorly smooth and weakly alutaceus in parts. Scutellum smooth, mostly glabrous with scattered setae along margins. Scutellar sulcus deeply crenulate. Mesoscutellar trough and metanotum costate. Propodeum mostly polished with irregular surface; with prominent transverse carina separating dorsal and posterior aspects; dorsal aspect with two pairs of longitudinal carinae; posterior aspect with strong v-shaped median carina; dorsal aspect distinctly longer than posterior. Notauli absent. Pronotum mostly smooth and polished, with shallow and crenulate ventral groove. Mesopleuron smooth and devoid of setae; sternaulus sinuate, long and crenulate. Metapleuron costate, rugose posteriorly, spiracle indistinct.

Wings. Fore wing vein r absent, 2RS and 3RS distinctly apart, both veins merging into stigma, vein R1 0.2× stigma length; stigma 2.2 time longer than high.

Legs. Hind tibial spurs 0.25× the hind tibia length. All legs smooth. Mid coxa with transverse sulcus dorsally. Hind tibia weakly enlarged apically, narrower than hind femur, 4.6× longer than maximum width

Metasoma. All terga smooth. Mid-longitudinal furrow at base of T1 margined by carina laterally.

Male. Essentially as female except body length 1.7 mm; fore wing length 1.5 mm; flagellomeres not expanded ventrally; and wings hyaline (as compared with distinctly banded in ♀).

Diagnosis. Adelius nigripectus was formerly distinguished by the mostly smooth body surface, as compared with other species, and the hyaline wings; however, the female has a faintly banded fore wing. The dorsal aspect of propodeum is uniquely long in this species, being about two× longer than the posterior aspect, and the transverse carina on the propodeum is strongly prominent. In addition, the mid-basal sulcus on T1 is margined by weak carinae laterally. The color variation in A. coloradensis makes difficult to separate it from A. nigripectus by color alone; however, the color of the hind tibial spurs in A. coloradensis are consistently brown, as is also the hind basitarsus, whereas in A. nigripectus the spurs are yellow, contrasting with the brown basitarsus. The main difference between these two species is the shape of head, being wider at the temples in A. coloradensis , and the setae and sculpturing of scutellum, which is smooth and mostly glabrous in A. nigripectus , as compared to being punctate and densely setose in A. coloradensis .

Biology. This species has been reared from a leaf-miner larva on poplar ( Salicaceae ).

Distribution. Recorded only from the US states of Indiana and Kansas.

Figures

FIGURES 86–91. Adelius nigripectus Muesebeck. 86–89, holotype, ♂: 86, habitus, dorsal; 87, head, dorsal; 88, wings; 89, propodeum and T1–3. 90–91, non-type, ♀: 90, habitus, lateral; 91, head and mesonotum, dorsal.