Calyxochaetus brooksi Runyon, 2024, sp. nov.

Calyxochaetus brooksi sp. nov. (Figs 28, 40, 69, 74) Type material. HOLOTYPE ♂, labeled: “ USA: AZ: Chiricahua Mtns./ creek nr. Ash Spring, 5800–/ 6100ꞌ, 31°52.3′N 109°14.0′W / 17.viii.2007, swp, S.E. Brooks ”; “HOLOTYPE/ Calyxochaetus / brooksi / J.B. Runyon [red label]” (CNC) (Fig. 69). PARATYPES: USA: Arizona: Same data as holotype (4♂, CNC). Diagnosis. This species is distinguished from others in the C. cilifemoratus species group by the combination of yellow metepimeron (Fig. 69), arista-like stylus with small apical lamella (Fig. 28), and foreleg with tarsomere 3 twice as long as tarsomere 4 (Fig. 40). Description. Male. Wing length 2.3–2.4 mm. Head: Frons thinly brown pruinose with violet ground color visible, not glabrous. Face (Fig. 69, inset) silver with weak yellow tinge, triangular, eyes essentially contiguous (less than 1 ommatidium wide) at clypeus.Antenna (Fig. 28) brown, scape yellow-brown; scape laterally flattened, shorter than postpedicel; postpedicel elongate oval, about 1.5X as long as wide; arista-like stylus indistinctly thickened and microtrichose with small, narrow, oblanceolate apical lamella. Palpus small, oval, brown with whitish apex. Thorax: Pleura brown with thick gray pruinosity, usually yellowish below halter and along sutures; metepimeron wholly yellow. Legs: Foreleg: Coxa, femur and tibia wholly yellow, tarsus brown from near middle of tarsomere 3. Tibia slender, without outstanding setae. Tarsus (Fig. 40) with tarsomere 1 very short, about as long as wide. Tarsomere 2 with small (about half tarsomere 3 length), yellow, distally projected anterior seta at apex. Tarsomere 3 twice as long as tarsomere 4. Midleg: Coxa, femur and tibia wholly yellow, tarsus brown from apical fourth of tarsomere 1. Tarsomere 1 with 2 fine curved anterior setae (one long, one shorter) at apex. Tarsomere 2 with basal half slightly swollen and bearing 3–4 fine sinuous yellow anterior setae. Tarsomere 4 with fine sinuous yellow anterior seta at apex. Tarsomere 5 with 1–2 shorter, fine anterior setae. Tarsomeres decreasing in length apically, tarsomere 1 subequal to combined length of tarsomeres 2–5. Hindleg: Yellow, except apex of femur light brown, apex of tibia becoming brown, tarsus wholly brown. Femur with anteroventral row of slender yellow setae, those on basal half short but increasing in length on distal half with 2–4 long (longest 1.5X femur width) setae on apical half (similar to Fig. 51), posterior preapical seta absent. Tibia with indistinct ventral row of short, slender setae (less than tibia width) on basal third, with small ventral seta near 1/2 and 3/4. Wing: Similar to C. hardyi (Fig. 58) except: Anterior half of wing brown tinged. Abdomen: Tergite 1 yellow-brown. Tergite 2 almost wholly yellow, narrowly brown along posterior margin. Tergite 3 mostly yellow, brown dorsally and along posterior margin. Tergite 4 brown, sometimes with some yellow laterally near base. Basal sternites yellow with sternites 4–5 becoming brown. Female. Unknown. Distribution and seasonal occurrence. Known only from the type locality in the Chiricahua Mountains in southeastern Arizona (Fig. 74). Adults were collected in August. Etymology. Named in honor of the dipterist Scott Brooks, who collected all known specimens of this species.