Empis (Enoplempis) occidentalis Sinclair, Brooks & Cumming, 2025, sp. nov.
Creators: name: Sinclair, Bradley J.
name: Brooks, Scott E.
name: Cumming, Jeffrey M.
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Empididae
Empis
Empis occidentalis

description: Empis (Enoplempis) occidentalis sp. nov.
urn:lsid:zoobank.org:act: 91BBA842-C556-4255-8A74-CBFBD2F75672
(Figs 28–31, 35–37, 40)
Type material. HOLOTYPE ♂, labelled: “U.S.A.: CALIFORNIA:/ Marin County, Liberty Gulch, Mt. Tamalpais [37°57′N 122°37′W]/ 27-IV-1978 D. Wilder ”; “ D. Dee Wilder / Collection [yellow label]”; “ HOLOTYPE / Empis (Enoplempis) / occidentalis Sinclair,/ Brooks & Cumming [red label]” (CAS). PARATYPE: USA. Oregon: Benton County: Corvallis [44°34′N 123°16′W], 10.v.1930, J. Wilcox (1♂, USNM).
Possible additional material (unassociated females). USA. Washington: Jefferson County: 6 km W Olympic NP [47.819°N 124.251°W], trib. of Hoh R, 6.vii.1989, BJS (2♀, CNC). Pacific County: Hwy 401 W of Naselle, 46°18.566′N 123°48.073′W, 13.vii.2013, Bean Ck, 40 m, BJS (2♀, CNC); Pierce County: Elbe [46°45′N 122°11′W], 27.vi.1935, ALM (1♀, USNM).
Diagnosis. This species is distinguished from other species of the E. (En.) arrecta species group by a single narrow process on the male hind tibia, hind tibia strongly clavate with setae longer than width of tibia (Fig. 29), scutum with three brownish vittae and male cercus with hooked lobe basally.
Description. Wing length 5.3–6.1 mm. Male. Similar to E. (En.) diokra sp. nov., except as follows: head with eyes closely approximated, narrowly separated by less than width of anterior ocellus. Face slightly divergent towards mouthparts.
Thorax with brownish vittae along acr row and dc rows in anterior view (Fig. 28).
Legs with apical swelling of hind femur and apical half of hind tibia darker. Hind femur with 3 slender, curved finger-like processes, middle process with blackened apex; apex with preapical row of ca 10 flattened, black, curved posteroventral setae, proximal setae closely approximated and distal setae ca half-length of straighter proximal setae; preapical anterior seta not strongly developed (Figs 29–31). Hind tibia arched with narrow base and strongly expanded on distal half; anteroventral digitiform process long, projecting obliquely to posterior side of tibia; process with anterior margin with very short, knob-like setae, long setae confined to apex; without posteroventral process; with seta dividing in half posteroapical comb; apical half of tibia with anterodorsal and posterodorsal setae twice as long as width of tibia (Figs 29–31). Hind tarsus with tarsomere 1 somewhat inflated, half width of expanded tibia.
Abdomen dark, shiny, without pruinescence, with pregenital segments mostly unmodified; tergite 6 with posteroventral corner slightly prolonged, rounded; tergite 6 with thickened posterior margin, slightly prolonged laterally, overlapping tergite 7; tergite 7 with thickened posterior margin; sclerites of segment 8 thickened, fused laterally. Terminalia (Figs 35–37): dark reddish brown with hypandrium shiny, phallus orange brown. Cerci fused medially; erect, projecting dorsally with crown of dense, black setae; posterior margin with small, rounded projections; base expanded into short, hooked lobe with slender dorsal setae; base without prolonged posteriorly directed hooked lobe. Subepandrial process not developed. Epandrial lamella with broadly rounded, expanded posterior margin, longer than high; broadly fused with cercus anteriorly; posterior margin without knob-like projection; setae short along posterior margin. Hypandrium broad, expanded, enclosed by epandrial lamellae; apex truncate, rounded; without setae. Phallus with outer expanded sheath on basal two-thirds; apex of sheath with pointed extension and inner longer extension bearing ventrally projected lobe with apex jagged, tooth-like; phallus projecting from posterior margin of basal sheath, extending between base of cerci with slightly arched narrow section; posterior margin of phallus with spiny projections (Figs 36, 37); ejaculatory apodeme more than half-length of epandrium, T-shaped, with lateral apodemes near lower margin of central apodeme.
Female. Similar to male, except as follows: frons slightly broader than width of anterior ocellus; hindleg without modified setae and processes; hind femur with fine, white pile beneath.
Geographical distribution and seasonal occurrence (Fig. 40). Empis (En.) occidentalis sp. nov. is known from California and Oregon, and possibly Washington. Adults have been collected from April to July.
Etymology. The species name is Latin for western, in reference to the western North American distribution of this species.
Nuptial gift presentation. Form unknown.
description: Published as part of Sinclair, Bradley J., Brooks, Scott E. & Cumming, Jeffrey M., 2025, Revision of the western Nearctic species of Empis subgenus Enoplempis (Diptera: Empididae), pp. 1-200 in Zootaxa 5615 (1) on pages 16-17, DOI: 10.11646/zootaxa.5615.1.1, http://zenodo.org/record/15217957