Mythenteles propleuralis Melander
Creators: name: Evenhuis, Neal L.
Publisher: name: Zenodo
Year: 2003
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Bombyliidae
Mythenteles
Mythenteles propleuralis

description: Mythenteles propleuralis (Melander)
(Figs. 3, 5, 27, 33)
Empidideicus propleuralis Melander, 1946: 458. Painter & Painter, 1965: 416; Hull, 1973: 275; Evenhuis, 1983: 485.
Mythicomyia mutabilis Melander, 1961: 229. Painter & Painter, 1965: 418; Hull, 1973: 269; Evenhuis, 1983: 481.
Mythicomyia (Mythenteles) mutabilis Melander. Hall & Evenhuis, 1986: 337.
Empidideicus (Cladella) propleuralis Melander. Hull, 1973: 273.
Cladella propleuralis (Melander). Hall & Evenhuis, 1987: 618; Evenhuis, 1991: 28.
Mythenteles propleuralis (Melander). Evenhuis, 1991: 53; Evenhuis, 2002b: 36
Mythenteles mutabilis (Melander). Evenhuis, 1991: 53.
Evenhuis (1991: 53) dealt with the generic synonymy of Cladella and Mythenteles and the generic placement and specific synonymy of Mythenteles propleuralis and M. mutabilis. Recent comparison of the male and female genitalia of both M. propleuralis and M. mutabilis confirm that the two species are conspecific.
DESCRIPTION. Male. Length: 1.2–3.0 mm. Head. Ocelli not forming an equilateral triangle, lateral ocellus 1 x its diameter from inner eye margin; eyes dichoptic, separated at vertex by 1.5 x width of ocellar tubercle; frons shining black to chocolate brown on upper 1/2, lower 1/2 yellow, with scattered minute pale yellow hairs; face yellow, a few pale hairs at tip of oral margin; oral margin and gena black; occiput dark brown to black, shining, with sparse pale yellow hairs; areas surrounding lower oral margin paler than occipital color, sometimes tending to orange; antenna (Fig. 3) black, segment I minute, segment II width nearly 2 x length, first flagellomere short, ovoid, ca. 1.5–2.0 x as long as wide, second flagellomere slightly longer than width of first flagellomere, sensillum apical; proboscis brown to black, varying from slightly projecting beyond oral margin to projecting for slightly more than head height.
Thorax. Mesonotum and scutellum subshining to shining black to chocolate brown; spot on humeral callus, extremely narrow lateral margin, and postalar callus narrowly yellow; mesonotal hair short, scattered, white; pleura black, sclerites vaguely outlined with yellow, if at all; halter with stem testaceous, knob creamy white, some specimens with dark brown color dorsally on knob.
Wing (Fig. 5). Hyaline to subhyaline, with microtrichiae throughout; veins brown; costa ends slightly less than halfway between end of R4+5 and M1; Rs connected to R1; R2+3 ending in R1 just beyond level of r­m crossvein; R4+5 slightly curved toward wing margin; dm­cu crossvein present, partially present, or absent; CuA1 thickened at base, thin on apical 3/5; fringe of hairs on posterior margin of wing dense, short.
Abdomen. Dorsum shining black to chocolate brown, with sparse white hairs; tergites rarely with vague yellow fascia (if present, most pronounced on apical tergites); venter brownish to black.
Genitalia (Fig. 27). In lateral view with gonocoxae thin, L­shaped; gonostylus small, subconical, tapering to bluntly rounded apex; epiphallus broad on upper 1/2, partially sheathing aedeagus, tapering to long, thin paired go0nocoxal apodemes on lower 1/2; aedeagus bulbous basally, extending posteriorly as thin tapered structure inside parameres; aedeagal apodeme small, subreniform, with basal pedicel; lateral rami reduced, thin, ellipsoidal; epandrium subquadrate, pseudosurstylus long, blunt apically; cercus subtriangular.
Female. As in male except as follows: propleuron and upper margins of katepisternum and anepimeron yellow; female genitalia (Fig. 33) with vaginal furca U­shaped, lateral and medial processes short, subequal in length, forming paired Vs; spermathecal reservoir conical, basal portion tapering to apical spermathecal duct; apical spermathecal duct extremely thin, length about 2 x that of spermathecal reservoir; sperm pump without musculature, hyaline; apical valve large, sclerotized, cylindrical, 2 x as wide as sperm pump; basal spermathecal duct broad, hyaline, leading to common duct; crescent­shaped sclerite at vaginal orifice between medial processes of vaginal furca.
Types. Melander (1946) originally described M. propleuralis based on “three specimens” (Melander did not state the sexes of these specimens, but examination of the type series in this study shows them to consist of 1 male and 2 females). The best preserved of these, a female, from UNITED STATES: California: S. Fork Santa Ana River, 16.vi.1945, A.L. Melander, was designated by Hall & Evenhuis (1987: 620) as lectotype. The lectotype and paralectotypes were reexamined during this study. They are deposited in the USNM.
Holotype male of M. mutabilis [not female as stated by Hall & Evenhuis (1986: 337)] from UNITED STATES: California: San Diego County: Live Oak Park, 24.v.1944, A.L. Melander deposited in the USNM. The holotype and the paratypes listed by Melander (1961) were reexamined during this study.
Var ia t io n. I have examined a few specimens in which one wing has cell dm closed while the other wing has cell dm open or partially closed or both wings have cell dm partially closed. However, no specimens have been seen that have both wings with cell dm completely open.
Remarks. With the designation of the lectotype, the type locality of M. propleuralis can be restricted even further to the San Bernardino Mountains, 6250 ft [1905 m], near the junction of the south and east forks of the Santa Ana River, not far from the headwaters. Melander had a cabin in Barton Flats, near this area, and did a great deal of collecting of mythicomyiids and other micro­asiloids and empidoids there between 1944 and 1947, usually by sweeping flowers.
Distribution. Probably restricted only to California. Hall & Evenhuis (1986, 1987) recorded M. propleuralis and M. mutabilis from Arizona, California, Nevada, and Washington states. In this study, specimens identified as M. propleuralis and M. mutabilis that had been previously recorded from Arizona and Nevada are placed in the new species M. silus described below and should be removed from the distribution range of M. propleuralis. I have not been able to examine specimens from Washington and, until such time as specimens become available for study, this state should be left as questionable for M. propleuralis.
description: Published as part of Evenhuis, Neal L., 2003, World revision of the microbombyliid genus Mythenteles Hall & Evenhuis (Diptera: Mythicomyiidae), pp. 1-28 in Zootaxa 346 on pages 19-22, DOI: 10.5281/zenodo.157139