Eosphaerophoria marginata Frey, 1946.
Frey, R. (1946) Uebersicht der Gattungen der Syrphiden-Unterfamilie Syrphinae (Syrphinae + Bacchinae). Notulae Entomologicae 25 [1945], 152-172.
Frey (1946) based E. marginata on a series of 3 male and 1 female specimens from the Philippines collected by G. Boettcher in June and July 1914, which are deposited in the Helsinki collection (ZMUH). From these syntypes, a pinned male labelled “Luzon. // Banahao // VII. 1914” “Paratype” [red label] “Mus. Zool. // Helsinki // N:o 5728” [number handwritten] “Mus. Zool. Helsinki // Loan No. // D 2009-26” was designated as the lectotype to fix and ensure the universal and consistent interpretation of the name by Mengual & Ghorpadé (2010). The other syntypes were labelled as paralectotypes.
Male. Head. Face straight, with distinct round tubercle, yellow, yellow pilose; gena yellow; lunula black; frons completely black on dorsal 1/2 (length between anterior ocellus and lunula), yellow on basolateral 1/2 with medial black vitta narrowing ventrally, about 1/3 of the facial width at the narrowest point, with frontal sulcus defining dorsal completely black area, with few short yellow hairs ventrally; dichoptic; vertex and vertical triangle black; ocelli brownish; antenna yellow, basoflagellomere darker dorsally, oval; arista dark brown; occiput mainly black, yellow ventrally, yellow pilose.
Thorax. Scutum mainly black, shiny medially, black pollinose laterally, yellow laterally with a lateral broad yellow stripe from postpronotum to scutellum with some black hairs, golden brown pilose; postpronotum yellow; notopleuron yellow with distinct posterolateral obtuse protuberance; scutellum triangular, yellow with dor- somedial triangular black area continuing from posterior mesonotum, brownish pilose; propleuron, anepisternum and anepimeron entirely yellow; katepisternum black with dorsal yellow macula; meron black; katepimeron yellow; katatergum mainly yellow, black posteriorly; calypter dark brown; halter orangish yellow. Wing. Wing bare basomedially. Legs. Pro- and mesoleg entirely yellow, except distal part of mesofemur and basal part of mesotibia dark, yellow pilose except tarsi with short black setulae ventrolaterally; metacoxa and trochanter yellow; metafemur yellow on basal 1/2, black on distal 1/2; metatibia black; metatarsus black, golden yellow and black pilose.
Abdomen. Dorsum mainly black, black pilose except 1st tergum and anteriorly 2nd tergum yellow pilose laterally; 1st tergum black, yellowish on basal and lateral margin; 2nd tergum black dorsally, narrowly yellow laterally on basal 3/4 continuing the yellow margin of 1st tergum; 3rd tergum black with basoanterior very narrow black fascia not reaching margins and with basal narrow yellow fascia (about 1/5 of tergum length) produced posteriorly in a medial small triangular emargination, with lateral margin yellow on anterior 1/2; 4th tergum similar to 3rd, black with ba- soanterior very narrow black fascia not reaching margins and with basal yellow fascia produced posteriorly in a medial small triangular emargination, broader than yellow fascia of 3rd tergum (about 1/4–1/3 of tergum length), with lateral margin yellow on anterior 1/2; 5th tergum black with 2 lateral triangular yellow maculae on basal 1/3, leaving median 1/2 or more black; 6th tergum yellowish, black medially; sterna yellowish, yellow pilose except 4th sternum with some long thin black hairs medially on posterior margin; 3rd sternum slightly produced medially into a projection with 2 tips narrowly separated with black setulae close to posterior margin; 4th sternum with posterior margin produced medially into 2 projections with black setulae; male genitalia as figured.
Female. Paralectotype female lacks the head, but some details are known from original description. Similar to male except for normal sexual dimorphism and face yellow with a medial black vitta. Legs: probasitarsomere dark yellow, darker than other tarsomeres; metafemur slightly more yellow basally, about 3/5, black on apical 2/5. Abdomen: 3rd and 4th terga similar to male but anterior yellow fascia narrower and posterior emargination smaller; 5th tergum with 2 long yellow maculae on anterior 1/2, leaving a narrow black fascia medially on anterior margin; 6th tergum black. Sterna yellow pilose, with black pile after 5th sternum.
Variation. Examined paralectotype male has the 4th abdominal tergum broken, placed in a microvial with the genitalia and the rest of the terga. The non-examined paralectotype male lacks the head.
The female from Thailand presents some variation compared with the female from the Philippines: face yellow with medial black vitta narrowing down to oral apex; frons completely black on dorsal 1/4 (length between anterior ocellus and lunula), yellow on basolateral 3/4 with a media broad black vitta, about 3/4 of the facial width, without frontal sulcus. Scutellum with few short black pile on posterior margin. Mesotibia with a medial small yellowish macula, not well-defined and could be the result of the use of forceps to arrange the legs. Abdomen similar except 5th tergum with a smaller yellow maculae, leaving median 1/3–1/2 black.
unless otherwise stated