Tetracis formosa (Hulst)

Ferris, Clifford D. & Schmidt, Christian, 2010, Revision of the North American Genera Tetracis Guenée and Synonymization of Synaxis Hulst with Descriptions of Three New Species (Lepidoptera: Geometridae: Ennominae), Zootaxa 2347, pp. 1-36 : 22-23

publication ID	https://doi.org/ 10.5281/zenodo.275566
DOI	https://doi.org/10.5281/zenodo.6209067
persistent identifier	https://treatment.plazi.org/id/03BF6D3A-FFE0-DF6D-68C4-174CFF3BFE1A
treatment provided by	Plazi
scientific name	Tetracis formosa (Hulst)
status

Treatment

( Figs. 63–68 View FIGURES 57 – 71 , 98 View FIGURES 95 – 101 , 113 View FIGURES 102 – 117 , 130 View FIGURES 125 – 132 , 143 View FIGURES 143 – 145 )

Gonodontis formosa Hulst, 1896 . A classification of the Geometrina of North America, with descriptions of new genera and species. Transactions of the American Entomological Society. 23(3):375. Two syntypes: ♂ San Bernardino Co., California (Type USNM 3910, missing abdomen and no genitalic side); ♀ Glenwood Springs [Garfield Co.], Colorado (no USNM type label, dissected). [USNM]. Note: Barnes & McDunnough illustrated a male “ type ” of Gonodontis formosa from Glenwood Springs, Colorado (1912, Pl. XVI, fig. 5).

Synaxis formosa McDunnough, 1938 , page 173, entry 5193.

Diagnosis: Tetracis formosa separates from its congeners by its gray to gray-brown DFW color (paler at low elevation in Caifornia) and the following characters: narrow, wavy black or dark brown PM line; black or dark brown AM line that angles diagonally outward and upward from inner margin, terminating at the dark discal spot; dark submarginal line or band.

Description: Adults ( Figs. 63–68 View FIGURES 57 – 71 ): FWL: 17–23 mm. Antenna nearly white dorsally, bipectinate in male, nearly filiform in female and densely setose ventrally. Palpi broad about 1.5x eye width, speckled with gray, brown, and black scales. Head (frons gray), abdomen, legs gray to gray-brown, varying in color according to habitat. Montane specimens are mostly gray, high-desert specimens gray-brown, becoming paler at lower elevations in California (Los Angeles Co.). Ventral abdomen, legs paler and flecked with dark brown scales. Thorax dorsally and ventrally hirsute. Wings: Base color pale gray to white; overall aspect gray to gray-brown because of overlying gray, brown, and dark brown scales. FW apex acute but barely falcate. AM and PM lines dark brown; PM line narrow, sinuate, with a narrow white outer border its entire length. AM line with narrow white border basad; AM line angles diagonally outward and upward from inner margin, terminating at the dark discal spot. MB at most only slightly darker than basal area. Submarginal area divided by narrow irregular dark brown band; in many specimens the wing color is paler distad of this band. Veins outlined in white. DHW paler centrally with darker shading along outer margin; dark brown median line irregular, usually well-developed; discal spot small and dark. Wings ventrally very pale, lightly irrorated by brown scales. PM line, DHW median line, and discal spots strongly repeated; AM line indistinct. Male genitalia ( Figs. 98. 113 View FIGURES 95 – 101 View FIGURES 102 – 117 ): Uncus of medium width, slightly decurved, tapering to bluntly pointed tip. Dorso-caudal margin of gnathos concave and irregular, with a slender tapering upcurved spine at either side. Furca short (ca. 0.4x width of valve base) from middle of anellus tapers uniformly to sharply-pointed apex. Valve broad with even margins, tapering to rounded apex with a robust sharply-pointed apical projection at the dorsal margin. Aedeagus with a ring of slender spinules at posterior end at base of vesica including a group of long setae; everted vesica with small unsclerotized dome; a pouch or diverticulum below dome. Female genitalia ( Fig. 130 View FIGURES 125 – 132 ): A/P = 0.63. Length of lightly sclerotized tubular ductus bursae is ca. 0.75x length of corpus bursae. Corpus bursae elongated and ovoid with irregularly-shaped dentate signum.

Material examined: 279 specimens with 6 dissections.

Biology: Incompletely known. A museum specimen examined was reared from a wild-caught larva on Prunus andersonii Gray (Desert Peach) from Washoe Co., Nevada. Habitats range from desert riparian canyons (Colorado, Utah) to dry coniferous forest (Wyoming). Adults in early September to late November.

Distribution ( Fig. 143 View FIGURES 143 – 145 ): Colorado, eastern Utah, and eastern Wyoming west to Caifornia and north to southern British Columbia and southern Alberta from 2850–7600’ (870–2320m). Records by province/state/ county are: CANADA: ALBERTA. NE of Brooks. UNITED STATES: CALIFORNIA. Alpine, El Dorado, Inyo, Lassen, Los Angeles, Modoc, Mono, Riverside, San Bernardino, San Luis Obispo, Santa Cruz, Ventura. COLORADO. Mesa. IDAHO. Owyhee. NEVADA. Washoe. OREGON. Harney. UTAH. Grand, San Juan, Sevier, Utah. WASHINGTON. Kittitas. WYOMING. Albany, Washakie.

Discussion: It is possible that the California arid region populations represent a sibling species of T. formosa , but no genitalic differences were noted. Suitable specimens were not available for molecular analysis.