Pericompsus (Pericompsus) ephippiatus (Say 1830)

Pericompsus ephippiatus (Say)

Bembidium ephippiatum Say, 1834:439. [Type lost. Neotype designated by Lindroth and Freitag (1969:338) in MCZ. Type-locality: Indiana.]

Tachys ephippiatus (Say).—LeConte 1848:468.

Pericompsus ephippiatus (Say).—LeConte 1851:191.

DESCRIPTION.—Form (Figure 59): Moderately elongate and narrow; head and prothorax much narrower than elytra; dorsum barely convex; elytra narrowed apically. Easily recognized in the United States by the absence of microsculpture; for Mexico see the key.

Color: Shiny testaceous; middle of venter rufous; elytral cloud shape various (see below), pale rufous to piceous.

Head: Narrower across eyes than pronotum, frontal furrows moderately impressed and evenly arcuate, each extended to posterior margin of eye: eyes large and prominent.

Pronotum (Figure 59): Subcordate, sides shallowly sinuate in basal half; base broadly lobed; hind angles acute, prominent; side margins not reflexed; disc moderately convex.

Elytra: Each elytron with 6 punctate interneurs; punctures contiguous and more or less striate; rows 1–5 less impressed apically, 6 effaced apically; interneur 7 effaced externally throughout, in some specimens seen as a shadow through transparent cuticle; interneur 8 well impressed and foveate just anterior to middle; fovea large, slightly wider than elytral explanation; humeral margin strongly rounded at base, not connected with base of interneur 4; side margins moderately explanate, minutely serrate-setulose in basal fourth; chaetotaxy Eo–1a, 2a, 3a, 4e, 5a, 6a, 7, 8b and Ed–1, 3a, 5b, 7b, 8; plica long and well developed externally.

Microsculpture: Mostly effaced except near scutellum and in frontal furrows, where it consists of large transverse reticulation.

Genitalia: Male (Figure 66) (10 examined); female (2 examined).

Size: Length, 2.32–3.00 mm; width, 1.00–1.20 mm; 10 specimens measured.

VARIATION.—This is a constant species in regard to form and size, although I saw a few very small individuals (2.32 mm). The elytral cloud is various, always present, but ranging from two small isolated spots—one on each elytron—at the apical third (rare) to one, large, central, piceous to rufous cloud extended from base to apex along the suture and not reaching the lateral margins. These variations occur within population samples.

NATURAL HISTORY.—Several specimens were collected at “black-light.” The flight wings are long; therefore, there is little doubt the beetles are capable of flight. Specimens were collected in Mexico in June through September and January, March, and November. For the United States, specimens are recorded only from the warmer months, May to October. Teneral specimens from Louisiana, Texas, and Guerrero, Mexico, were collected in July. The habitat is riparian. My wife La Verne and I collected members of this species running on wet sandy clay flats along the Republican River near Scandia, Kansas, where there was little or no vegetation.

DISTRIBUTION.—The range of this well-collected species extends from Massachusetts to Kansas, south through Texas as far as Honduras. It does not occur on the west coast of the continent north of Jalisco.

LOCALITY RECORDS (Figure 73).—I have seen 287 specimens from the following localities:

UNITED STATES: ALABAMA: Dallas County, Selma (MCZ, USNM); Mobile County, Mobile (MCZ); Tuscaloosa County, Tuscaloosa (UASM). ARKANSAS: Hempstead County, Hope (MCZ). DISTRICT OF COLUMBIA: (USNM). FLORIDA: Alachua County, Gainesville (USNM); Highlands County, Highlands Hammock State Park (USNM). ILLINOIS: Randolph County, Fort Chartres (MCZ), Fort Chartres Landing (USNM); Saint Clair County, Cahokia (MCZ). IOWA: Des Moines County, Burlington (MCZ); Henry County, Mount Pleasant (MCZ); Johnson County, Iowa City (USNM). KANSAS: Cloud County, Concordia on Republican River (UASM); Douglas County, Lawrence (MCZ); Republic County, Scandia on Republican River (USNM); Shawnee County, Topeka (USNM). KENTUCKY: Rowan County, Morehead (CNC). LOUISIANA: Caddo Parish, Shreveport (USNM); East Baton Rouge Parish, Baton Rouge (USNM); Jefferson Parish, Harahan (MCZ); Madison Parish, Tallulah (MCZ); Saint Helena Parish, Greensburg (RTAI); Parish unknown, Bay Sara (USNM). MARYLAND: Baltimore County, Baltimore (USNM); Montgomery County, Cabin John (USNM); County unknown, Chapel Point (USNM). MASSACHUSETTS: Franklin County, Northfield (MCZ): Hampden County, Springfield (MCZ). MISSISSIPPI: (MCZ); Adams County, Natchez (USNM). MISSOURI: Boone County, Easley (USNM); Saint Louis County, Creve Coeur Lake (MCZ); Saint Louis (MCZ, UMon); County unknown, “C. Mo.” (USNM). NEW JERSEY: Essex County, Orange (USNM); Gloucester County, Woodbury (MCZ). OHIO: (USNM). OKLAHOMA: Creek County, Sapulpa (USNM). PENNSYLVANIA: Allegheny County, (MCZ); Montgomery County, Arcola (MCZ); Pike County, Milford (MCZ, USNM). SOUTH CAROLINA: (MCZ); Charleston County, Charleston (UASM); Oconee County, Clemson College (USNM). TEXAS: Bexar County, San Antonio (USNM); Careron County, Brownsville (USNM); Cherokee County, Jacksonville (USNM); Colorado County, Columbus (MCZ); La Salle County, Cotulla (USNM); Val Verde County, Del Rio (MCZ), Devils River (USNM). VIRGINIA: Fairfax County, Clifton (USNM); Lee County, Pennington Gap (USNM); Mecklenburg County, Roanoke River at Route 1 (MCZ); Spotsylvania County, Fredricksburg (USNM).

MEXICO: CHIAPAS: 32.5 miles east of Comitan on Route 190 (UASM); 38.0 miles southeast of Comitan along Rio Grijalva at Puente de Chamic (RTBe); junction of Routes 190 and 195 (CNC). GUERRERO: 20.4 miles north of Chil-pancingo on Route 95 (UASM). JALISCO: Cihuatlan on Route 110 (UASM). OAXACA: 9.9 miles north of Pochutla on Route 175 (UASM); Rio Atoyac near Juchatengo (UASM); Tapanatepec (JNeg); 72.5 miles south of Valle Nacional on Rio Grande (UASM). SAN LUIS POTOSI: 6.0 kilometers west of Ciudad del Maiz (MCZ); El Naranjo on Rio El Salto (CAS).

CENTRAL AMERICA: GUATEMALA: Los Amates (USNM). HONDURAS: Rio Humuya northwest of Comayagua (USNM).

Pericompsus ephippiatus is a species of ground beetle in the family Carabidae. It is found in Central America and North America.