Holotype female, MALAYSIA: Selangor: Road B57, 0.8 km SSW of entrance of Selangor State Park, (3.3057,101.693) closed forest, Guek Hock-Ping, 27.i.2012 (California Academy of Sciences Collection).

Paratype: MALAYSIA: Sabah: Tawau, DR. Lim, 8.vii.1981, on Cocao (Natural History Museum, London).

Extensive black markings with white fenestrations in basal portion of both wings; forewing with basal four to five crossveins between R and Rs converging posteriorly, Rs closely approximating Psm basally; three crossveins between Cu1 and Cu2, 1st posterior marginal crossvein forked with posterior arm joining to Cu2 petiolate to margin; two dark spots across frons below antennae; single marking between antennal bases; dark markings medially on abdominal tergites 2–4; sternite seven with acuminate posteromedial margin with tuft of short dark setae.

Female: Wing length (forewing: 15.0 mm; hindwing: 13.5–14.0 mm). Overall colouration in live specimens bright green and yellow, with dark markings on head, abdomen and both wings (pale yellow in dried specimens). Head. Yellow with black marking on vertex between antennae and small quadrangular marking on frons below antennal base and proximal to eye margin; clypeus with brown suffusion laterally; labrum emarginate medially; antenna pale green but otherwise unmarked, slightly longer than forewing; flagellum with at least 50 flagellomeres; palpi green, unmarked. Thorax. Prothorax green with small brown mark anterolaterally on pronotum; setae short, green, and relatively sparse, darker and more dense laterally; mesonotum  and metanotum yellow green, scutum darker in preserved specimen, mesoscutellum pale yellow, setae sparse and pale yellow to white; legs very pale green with white setae, setae shorter and yellowish distally on foretibiae; distal tarsomere and claws brownish on all legs; wings relatively rounded, forewing costal area broad, rounded basally, then straight to wing apex; forewing with Rs sigmoid and closely approximating pseudomedial (Psm) basally; first five r-rs crossveins convergent, remaining crossveins sub parallel; seven inner gradate crossveins, meeting Psm; nine outer gradate crossveins; three crossveins between Cu1 and Cu2, 1st posterior marginal crossvein forked with posterior arm joining to Cu2, petiolate to margin; hind wing with five inner gradate crossveins, seven outer gradate crossveins; wing veins with setae relatively elongate and pedicellate, pedicels longer in basal portion of wing, setae colour corresponding to wing markings and colour of wing venation; wing hyaline with markings as per Figure 5, venation mostly pale green, forewing costal crossveins dark anteriorly on crossveins 1–3 and posteriorly on crossveins 8–10; basal subcostal crossvein dark; membrane infuscate and venation dark in medial area of both wings from R vein to posterior margin, markings darker posteriorly with cells (e.g. dcc, c2 and cu2) with white fenestration (Figs 1–4); basal portion of cell m2 infuscate; spot at base of wing on cubital vein; fourth posterior marginal crossvein dark distally. Abdomen. Yellow green dorsally, white ventrally; dark medial stripe on tergites 2–4; poorly defined dark spot laterally on tergites 3–5; sternite 8 with tuft of short strong setae medially. Female terminalia (Figure 6): Trichobothria ca. 25; sternite seven with broadly acuminate posteromedial margin with tuft of short dark setae; subgenitale relatively broad; spermatheca with vela relatively short and straight; ventral impression relatively shallow and wide; duct with slight coil.

The unusual new species is easily differentiated from all other species of Semachrysa by the distinctive wing venation mark between the antennal bases and only two spots across the frons, as well as the female abdominal sternite 7 being posteromedially acuminate with a tuft of strong setae. Only the female is known at this stage. Semachrysa jade sp. n. is similar in appearance to Semachrysa wallacei, based on head and wing markings. Like Semachrysa jade sp. n., Semachrysa wallacei is also only known from the female.

This new species is named after the daughter of the senior author, Jade Tanya Winterton.