Xestipyge conjuctum (Say)

Warner, William B., 2021, A brief review of the New World Xestipyge Marseul (Coleoptera: Histeridae: Dendrophilinae: Paromalini) with description of a new species from the southwestern USA, Insecta Mundi 2021 (854), pp. 1-12 : 3-4

Xestipyge conjuctum (Say)

Figures 1 , 3–4 , 17

Hister conjunctus Say 1825: 38 . Type locality: USA circa 1825 (based on article title).

Paromalus conjunctus: J.E. LeConte 1845: 68 ; Horn 1873: 306.

Carcinops conjunctus: Marseul 1855: 89 .

Xestipyge conjunctum: Lewis 1905: 37 ; Downie and Arnett 1996: 614; Bousquet and Laplante 2006: 219.

Diagnosis. Head weakly convex; disc mostly lacking coarse punctures. Pronotum with coarse punctures mostly restricted to lateral thirds and mostly single row along basal margin, row widening to about 2–4 punctures deep anterior to scutellum. Elytron with inner subhumeral weak and normally present in apical half only, occasionally extending to and sometimes fusing with humeral stria but lacking on humerus; outer subhumeral stria obsolete to sometimes represented medially by irregular puncture line, occasionally present near apex as well; dorsal intervals usually flat to weakly convex, sutural stria usually effaced in basal quarter to third, intervals between second dorsal and sutural stria usually with scattered punctures only in about apical third or less, declivity usually with distinct aciculations emanating from punctures at edge of declivity. Metasternum lateral to stria with coarse punctures scattered, mostly separated by half to two times their diameters with few subcontiguous, occasionally with coarse punctures denser, lateral metasternal stria variable: complete to metatrochanter to effaced in posterior quarter or third. In male: tegmen with parameres slightly shorter than basal piece, slowly triangularly expanding to widest width at apical 2⁄9, width slightly more than 1/3 length ( Fig. 17 ). Female with distinct chevronshaped incision on pygidial disc vaguely following free margin in apical half ( Fig. 3 ).

Length: 1.8–2.3 mm; total length: 2.0– 2.8 mm; widest width: 1.0– 1.9 mm.

Range. Extreme southeastern Canada to Florida and west to Texas ( Bousquet and Laplante 2006; Mazur 2011). I have examined specimens from the following states: USA: AR, IL, LA, MO, OH, NC, OK, SC, TX, WI.

Habits. Bousquet and Laplante (2006) list collections from tree hollows and cow manure. I have examined specimens collected in those habitats as well as wood chips, rodent (woodchuck and Neotoma sp. ) nests, horse manure, stable sweepings, Berlese of flood debris, and in Lindgren funnel traps.

Remarks. Xestipyge conjunctum is similar to X. geminatum , and is mostly sympatric with that species; characters to differentiate those two species are given under X. geminatum . On first appearance X. conjunctum is even more similar to X. skelleyi , but specimens of the latter are easily differentiated by their western distribution, (usually) complete (to arch) elytral sutural stria, much more elongate tegmen in males, and lack of any indication of an incised chevron on pygidium in females.

Figures

Figures 1–2. Dorsal habitus of Xestipyge species. 1) X. conjunctum, SC, USA. 2) X. geminatum, NC, USA.

Figures 3–5. Xestipyge species. 3) X. conjunctum, SC, USA, female pygidium. 4) X. conjunctum, right elytron. 5) X. geminatum, NC, USA, right elytron.

Figures 15–19. Xestipyge species tegmena, dorsal view. 15) X. garbigliettii, Durango, Mexico. 16) X. multistriatum, Veracruz, Mexico. 17) X. conjunctum, SC, USA. 18) X. skelleyi, holotype. 19) X. geminatum, NC, USA.