Pachybrachis connexus Fall, 1915

Barney, Robert J., 2019, Definition and Revision of the Pubescens Species-Group of North American Pachybrachis Chevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae), Including Descriptions of Three New Species, The Coleopterists Bulletin 73 (4), pp. 1017-1048 : 1020-1022

1. Pachybrachis connexus Fall, 1915 ( Figs. 1 , 13A ; Map 1A)

Pachybrachys connexus Fall 1915: 328 . Pachybrachis connexus: Riley et al. 2003: 156

(catalogue).

Type. Fall (1915) described P. connexus from a single female labeled “HotSprgs [printed] / 27.6 [hand-inked] Ar [printed, white paper] // Barber& / SchwarzColl [printed, white paper] // TYPE [printed] / connexus [hand-inked, white paper] // TYPE USNM [printed] / #71969 [hand-inked, red paper] // connexus [hand-inked] / Fall 1915 Revis. [printed, white paper] // USNM ENT / barcode / 0071322 [printed, white paper]”. This specimen was examined and photographed ( Fig. 13A ).

Redescription. Male. Rufo-testaceous, subsutural and marginal black stripes on elytra, connected narrowly along base and broadly along declivity ( Fig. 1 ); L = 1.86–2.28 mm (mean = 2.03 mm, n = 10); W = 0.91–1.15 mm (mean = 1.00 mm, n = 10); L/W = 1.95–2.08 (mean = 2.02, n = 10). Head: Distinctly wider than thoracic apex, HW = 0.66–0.78 mm (mean = 0.72 mm, n = 10); eyes narrowly separated, IOD = 0.11–0.17 mm (mean = 0.13 mm, n = 10); IOD/HW = 0.12–0.23 (mean = 0.18, n = 10); face primarily dark brown with white recumbent pubescence; antennae yellow-brown, not reaching elytral declivity. Pronotum: Rufo-testaceous, with faint M-shaped macula, covered with white recumbent pubescence; PL = 0.54–0.70 mm (mean = 0.64 mm, n = 10); PW = 0.82–0.96 mm (mean = 0.88 mm, n = 10); PL/PW = 0.65–0.80 (mean = 0.72, n = 10). Elytra: Yellow with subsutural and marginal black stripes connected narrowly along base and broadly along declivity, with white pubescence. Pygidium: Dark brown with white pubescence. Venter: Dark brown with white pubescence. Legs: Yellow with brown areas and white pubescence; front claws not enlarged. Genitalia: Median lobe in en-face view with large, oval OS, widest at ALM, abruptly narrowing to pointed terminus. Base to terminus straight in lateral view, though moderately inflated. Six males from three USA states were dissected.

Female. As in male, except L = 2.10–2.56 mm (mean = 2.31 mm, n = 10); W = 1.10–1.47 mm (mean = 1.19 mm, n = 10); L/W = 1.61–2.04 (mean = 1.95, n = 10); HW = 0.69–0.84 mm (mean = 0.77 mm, n = 10); IOD = 0.21–0.31 mm (mean = 0.25 mm, n = 10); IOD/HW = 0.27–0.35 (mean = 0.32, n = 10).

Remarks. Fall (1915) described this species based upon a single female from Hot Springs, Arizona, collected on 27 June by Barber and Schwarz. Fall’ s personal collection did not contain any examples (personal communication, Rachel L. Hawkins, MCZ). Pachybrachis connexus is readily identifiable among pubescent species due to the striping on the elytra.

Distribution. This species is found in southeastern Arizona, California, and Nevada (Map 1A). Nevada is a new state record. Hot Springs, Arizona is possibly Verde Hot Springs in Gila County.

Biological Notes. A large series of P. connexus were collected on E. fasiculatum in California. Some specimens were collected via UV blacklight in Arizona and California, and Malaise and pitfall traps in California.

Figures

Fig. 1. Pachybrachis connexus, Riverside Co., California. A–B) Dorsal and lateral habitus, respectively, C) Face, D) Pygidium, E–F) Median lobe of aedeagus, lateral and en-face views, respectively.

Fig. 13. Pachybrachis species, type specimens. A) P. connexus (female), B) P. integratus (female), C) P. morosus (female), D) P. haematodes (male), E) P. analis (female), F) P. marmoratus (female), G) P. desertus (male), H) P. brunneus (male), I) P. uteanus (male).