Dichelonyx pusillus ( LeConte, 1856 )

McPeak, Ron H., Lago, Paul K. & Hanley, Guy A., 2020, Two New Sulcate Species of Dichelonyx Harris (Coleoptera: Scarabaeidae: Melolonthinae: Dichelonychini) from Southern California, USA and Baja California, Mexico, The Coleopterists Bulletin 74 (1), pp. 45-59 : 57

Dichelonyx pusillus ( LeConte, 1856)

( Figs. 20–26 )

Dichelonycha [sic] pusilla LeConte 1856: 282 .

Specimens of this species are typically uniformly dark brown, occasionally with the central elytral disc paler brown. The anterior clypeal angles of males ( Figs. 20–22 ) and females ( Figs. 23–24 ) are slightly rounded, with the lateral margins slightly divergent to the base. The pronotum is unicolored. The elytral setae are white or silvery white and generally distributed from margin to margin, but never densely spaced, often vittate, with third, fifth, seventh, and ninth costae glabrous ( Fig. 25 ). The glabrous lines are generally more than half as wide as the setal bands. In some specimens, the setae are more evenly distributed, and the vittae are not at all apparent, but in these cases, the relatively sparse distribution of setae, along with the general dark coloration, is distinctive. The parameres are typical for genus, slightly angulate dorsally, with apically elongate lobes as robust in lateral view as those of D. magnesae or more so, with down-curved acute apices ( Fig. 26 ). The internal sac lacks sclerites.

Dichelonyx pusillus occurs widely in the southern half of California. The species has also been taken in western Nevada and in Baja California, Mexico ( Cornell 1971). The two new species occur sympatrically with D.pusillus only in the southern portion of its range.

Figures

Figs. 20–22. Dichelonyx pusillus, male. 20) Habitus; 21–22) Head, dorsal and oblique views, respectively.

Figs. 23–26. Dichelonyx pusillus. 23–24) Female head, dorsal and oblique views, respectively; 25) Female vittate elytra; 26) Parameres.