Liriomyza

Eiseman, Charles S., Lonsdale, Owen, Linden, John Van Der, Feldman, Tracy S. & Palmer, Michael W., 2021, Thirteen new species of Agromyzidae (Diptera) from the United States, with new host and distribution records for 32 additional species, Zootaxa 4931 (1), pp. 1-68 : 28-29

Updated key to the species of Liriomyza feeding on Euphorbia

1. Mesonotum with yellow longitudinal bands................................................................ 2

1′. Mesonotum largely black, without distinct yellow longitudinal bands............................................ 3

2. Back of head, at level of vertical bristles, entirely yellow. Acrostichal setulae less numerous (5 to 8), irregularly arranged in two rows...................................................................... Liriomyza euphorbiae Martinez [mine initially narrow and serpentine, developing into an irregular blotch; on E. kotschyana Fenzl and E. macroclada Boiss. ; Turkey]

2′. Back of head, at level of vertical bristles, partly brown. Acrostichal setulae more numerous, arranged in four almost regular rows...................................................................... Liriomyza heringi Nowakowski [mine a blotch; on E. esula L., E. nicaeensis All. , E. palustris L., E. salicifolia Host , and possibly E. amygdaloides L.; Lithuania, Romania, former Soviet Union]

3. Wings without vein dm-cu.............................................................................. 4

3′. Wings with vein dm-cu................................................................................. 5

4. Orbits between upper ors and vti completely yellow. Abdominal tergites without yellow lateral band. Penultimate section of M 4 2.5 to 3 times longer than last section.............................................. Liriomyza balcanica (Strobl) [mine broadly linear or a linear-blotch; on E. cyparissias L., E. esula , E. myrsinites L., and possibly E. amygdaloides ; Germany and Poland to Turkey]

4′. Upper part of orbits black. At least the basal part of abdominal tergite with yellow border. Penultimate section of M 4 maximum 2 times longer than last section................................................... Liriomyza myrsinitae Hering [mine a blotch preceded by a short linear portion; on E. myrsinites ; Bulgaria, Spain]

5. Orbits between upper ors and vti completely yellow. Mesophallus long, narrow, fused to distiphallus with broad, bilobed cuplike base from which one pair of short weakly scleritized tubules emerge.................. Liriomyza pascuum (Meigen) [mine a primary blotch, generally containing several larvae; on E. amygdaloides , E. characias L., E. dulcis L., E. esula , E. glareosa Pall. ex M.Bieb. , E. palustris , and E. pithyusa L.; throughout Europe]

5′. Upper part of orbits black. Phallus not as above............................................................. 6

6. Frons yellow at base of inner vertical seta. Distiphallus entirely split, short, with minute basal stem contrasting rounded apical chamber...................................................................... Liriomyza strigata (Meigen) [branching mine centered on the midrib; a polyphagous species, uncommonly reported from unspecified Euphorbia ; throughout Europe]

6′. Frons brown at base of inner vertical seta. If distiphallus entirely split and short ( L. huidobrensis ), then apical chamber narrow, not much wider than stem............................................................................... 7

7. Surstylus with two apical spines. Distiphallus angled dorsally, with very short apical chamber........................ 8

7′. Surstylus with one apical spine. Distiphallus various, but not as above........................................... 9

8. Eye 4.8–5.9 times higher than gena. Posterior margin of scutum along scutellum black. Ventral 2/3 of anepisternum brown. Femora entirely yellow. Left distal margin of basiphallus long, extending to apex of paraphallus. Basal stem-like half of distiphallus (fused to mesophallus) gradually narrowing to point of fusion with mesophallus............................................................................................ Liriomyza euphorbiella Eiseman & Lonsdale [mine initially narrow and linear with the frass in alternating strips, expanding to an elongate blotch with irregular and more or less diffuse frass; on E. heterophylla var. cyathophora ; USA]

8′. Eye 3.0 times higher than gena. Posterior margin of scutum narrowly yellow. Anepisternum yellow with brown clavate spot. Femora brown basally (paler on venter). Left distal margin of basiphallus shorter, not reaching apex of paraphallus. Basal stemlike half of distiphallus parallel-sided and abruptly wider than mesophallus.. Liriomyza euphorbivora Eiseman & Lonsdale [mine a roughly circular blotch on upper leaf surface, centered on the midrib, with frass in a few small, dark grains and lumps; on E. marginata ; USA]

9. Femora usually only brown basally, but sometimes more heavily mottled. Abdominal tergites narrowly yellow laterally. Acrostichal setulae (acr) between second and fourth pairs of dorsocentral setae in four more or less regular rows. Distiphallus simple, cup-shaped................................................................... Liriomyza sativae Blanchard [mine linear; a polyphagous species, with one questionable record from unspecified Euphorbia (light mining of E. pulcherrima observed in a laboratory setting, but no puparia were formed); North and South America; introduced in Europe, Asia, Africa, Australia, and several Pacific islands]

9′. Femora brown basally and with additional light to heavy dorsal mottling. Lateral margin of abdominal tergites brown. Acros- tichal setulae (acr) between second and fourth pairs of dorsocentral setae in two to three more or less regular rows. Distiphallus divided into one pair of short tubules......................................... Liriomyza huidobrensis (Blanchard) [mine linear, often following the midrib and lateral veins; a polyphagous species, uncommonly reported from unspecified Euphorbia according to Martinez & Sobhian (2000); the only record listed by Weintraub et al. (2017) is one of E. marginata from China; this South American fly is introduced in North America, Europe, Asia, and Africa]

Characters of the thorax of Liriomyza euphorbivora best differentiate it from other Liriomyza externally, as four rows of acrostichal setulae and a very narrow yellow posterior margin on the scutellum is not found in many species. In the United States, it occurs in L. eupatoriella Spencer , but this species has both vertical setae on yellow, the femora are entirely yellow (not basally brown) and the distiphallus is of a different structure, being more cup-shaped with the base strongly narrowed in lateral view. In Canada, the new species keys most readily to L. cracentis Lonsdale and L. agrios Lonsdale , although the spot on the anepisternum of these two species is much larger, their femora are entirely yellow, and the distiphallus is more cup-shaped, without a short apical chamber. The phallus instead shows more similarity to species without the posteriorly yellow scutum. These include L. conclavis Lonsdale (host unknown), L. asclepiadis Spencer and L. peleensis Spencer (both on Asclepias ), which have a medially constricted mesophallus and a very sharply upturned distiphallus, and L. subasclepiadis Spencer (also on Asclepias ), which also has a more strongly angled distiphallus.