Ephydra (Ephydra) mexicana Cresson

27. Ephydra (Ephydra) mexicana Cresson

Figs. 122–123, Map 27

Ephydra mexicana Cresson 1934: 214.— Wirth 1968: 22 [Neotropical catalog]; 1971: 369 [revision].— Mathis and Zatwarnicki 1995: 242 [world catalog].

Diagnosis. This species is similar to other subcongeners but may be distinguished by the elongate scutellum and setulose posterior margin of the anepisternum of the female and by characters of the male terminalia. Large shore flies, body length about 5.30 mm. General coloration.

Head: Mesofrons bluish with metallic luster. Head ratio 0.69; facial ratio 0.43. Eye ratio 0.88; gena-to-eye ratio 0.48; gena slightly darker than face, with some faint bluish and/or greenish coloration in addition to being gray.

Thorax: Scutum (vestiture and coloration); scutellum of female elongate, transversely rugose and distally pilose; prescutellar swelling of female not conspicuous but with some longer setae; acrostichal setae strongly developed, some seta-like; both males and females with well-developed pair of prescutellar acrostichal setae; anepisternum of female with posterior margin setose. Wing ratio 3.85–4.20 mm; costal vein ratio 0.25; M vein ratio 82. Legs greenish brown; tarsi and extreme bases of tibiae yellowish; tarsal claws about equal to length of 4th tarsomere.

Abdomen: Tergite 5 of male about equal in length to tergite 4. Male terminalia (Figs. 122–123): surstyli very short, blunt apically, markedly expanded dorsoventrally and flattened laterally in a broad, distally truncate lobe, posteroventral corner bluntly rounded, bearing a small setose lobe near base at medial margin of dorsal side; gonite with moderately broad base, tapered distally to sharply pointed, slightly curved blade; aedeagus slender, slightly sinuous in lateral view, with stout base, and slightly bent, blunt pointed apex.

Type material. The holotype male is labeled “Ƌ/ Mexico [handwritten]/ TYPE No. 6505 Ephydra MEXICANA E T Cresson, Jr. [red].” The holotype is double mounted, is in good condition (left basal flagellomere is missing), and is deposited in the ANSP (6505).

Type locality. Mexico. Distrito Federal: Valle de Mexico (19°40'N, 99°W).

Distribution (Map 27): This species is known only from the type locality, “ Mexico.”

Remarks. This species and E. pectinulata Cresson are sister species, as evidenced by the very similar structures of the male terminalia of both species. Nothing is known about the natural history of this species.

MAP 27. Distribution map for Ephydra mexicana Cresson.