Hemicrepidius palpalis ( Fall, 1907 )

Etzler, Frank E., 2020, A Revision of the Genus Hemicrepidius Germar, 1839 (Coleoptera: Elateridae) of the New World, with Comments on Global Classification, The Coleopterists Bulletin (mo 18) 74, pp. 1-126 : 75-76

Hemicrepidius palpalis ( Fall, 1907)

( Figs. 34a–d , 35b )

Athous palpalis Fall in Fall and Cockerell 1907: 229; Leng 1920: 170; Van Dyke 1932: 366; Lane 1971: 28.

Hemicrepidius palpalis (Fall) : Becker 1979a: 409.

Diagnosis. Hemicrepidius palpalis can be distinguished from all other Hemicrepidius by the straight to ear-like posterior margin of the hypomeron, the moderately long and dense setae on the pronotum, the dense, simple punctures on the pronotum, separated by a half puncture diameter or less, and an incomplete frontal carina.

It is most similar to H. falli and the key characters to separate the two are given under the diagnosis of that species.

Redescription. Length 8.5–12.0 mm, width 2.0–3.0 mm; color light brown to dark brown, elytra contrasting with pronotum, yellow-brown to brown, legs, antennae and sometimes posterior edge of pronotum, ventral edges of elytra, and edges of abdominal ventrites in many paler; integument shing. Setae moderately long, suberect, gray or yellow. Head: Punctures subumbilicate, nearly contiguous; integument shining; frons concave anteromedially, forming triangular impression in dorsal view; frontal carina broadly rounded, interrupted medially by punctures when viewed from front, frontoclypeal region reduced to narrow line or absent medially, frontal carina at most weakly projecting; eyes large and moderately bulging, ocular index 65–73 (n = 2); antenna weakly serrate, antennomere 2 subcylindrical, antennomere 3 subcylindrical, 1.5× length of 2 and with similar setation, antennomere 3 subequal in length to 4, antennomeres 4–11 about 3× longer than wide, densely setose throughout, antennomere 11 oval, at most with tip subtly constricted, antenna extending beyond pronotal posterior edge by 1.5–2.5 antennomeres. Prothorax: Pronotum as wide as long, widest at hind angles or just anterior of midlength; sides weakly arcuate, almost subparallel laterally, narrowing at anterior one-fourth; hind angles subparallel to weakly divergent, dorsal carina absent to very thin and low and appearing absent (visible only at high magnification, 50×); punctures on disc smaller than punctures on head, simple, separated by a half puncture diameter or less throughout, punctures larger and shallower laterally, subumbilicate; posterior edge with sublateral notches. Hypomeron with simple to subumbilicate punctures, nearly contiguous anteriorly, rarely separated by one puncture diameter, posterior one-fourth with semicircular impunctate area; posterior margin straight to ear-like ( Fig. 34b ) so hind angle not visible in lateral or ventral view. Prosternum with punctation matching punctation on hypomeron, separated by a half puncture diameter or less throughout; anterior lobe slightly deflexed, broadly rounded, partially covering ventral mouthparts; prosternal process curved dorsad between procoxae in lateral view, narrow and sinuate past procoxae. Pterothorax: Mesoventral cavity with lateral edges sinuate, not visible anteriad mesocoxae in lateral view; posterior edge of cavity truncate. Metaventrite with punctures simple, smaller than punctures on hypomeron, separated by half to one puncture diameter throughout. Scutellar shield elongate, about twice as long as wide, narrowly rounded posteriorly, sides sinuate, dorsal surface flat, anterior margin broadly rounded, setae radiating from midline, similar in length and color to setae on pronotum and elytra. Elytra at most weakly impressed basally; interstriae flat, punctures small and dense, giving wrinkled appearance; basal carina simple. Legs with lobe on tarsomere 3 largest, wide, visible dorsally, lobe on tarsomere 2 small and narrow, lobe on tarsomere 4 minute, usually visible only ventrally, lobe on tarsomere 1 smallest, visible ventrally. Abdominal ventrites: Punctures simple, slightly smaller than punctures on metaventrite, separated by one puncture diameter throughout; fifth ventrite narrowly rounded; lateral microserrations small, sometimes not visible on ventrite 5. Male genitalia ( Figs. 34c, d ): Parameres subparallel on basal twothirds, sinuate basal to sharply acute (<45°) preapical expansion, apex of paramere acute, membranous, setose ventral patch near pre-apical expansion and 3–5 apical dorsal setae. Median lobe narrow, gradually narrowing apically, basal struts broadly curved latero-basally. Basal piece with membranous area forming “W” shape medially.

Distribution. Specimens were examined from the following states: UNITED STATES: CA, OR, WA ( Fig. 35b ).

Notes. This species is apparently rarely collected. It appears to be limited to the northern Pacific coast, as far north as Queets, Washington, United States.

I have only examined males of this species. Larvae have not been associated.

Types Examined. Of Athous palpalis : Holotype: Medford, Or. / not in Lec coll./ palpalis Type/ H. C. Fall Collection / M.C.Z. Type #24370; male; type locality Medford, Oregon; in MCZC. Paratype: Humbolt [sic] Co., Cal.; male; in MCZC .

Specimens Examined (14). UNITED STATES: California: [Del Norte Co.], Cresent City, 25-VII- [1936]/ S.M. Williams Col (1, MCZC) ; Jebidiah Smith, Redwoods St. Park, VII-12-1968 / R. L. Westcott collector (1, CASC [ Figs. 34c, d ]) ; Humboldt Co., Eureka, Elk River Road , 19-VII- 1970, Brunson P. Bliven (2, CASC) ; Prairie Ck Redwoods , VIII-5-1975, F. G. Andrews (1, CASC [ Fig. 34a ]) ; Prarie Cr., State Prk. / VIII-2-1950, C.P. Alexander (1, MCZC) . Oregon: [Douglas Co.], Camas Valley , 6-17-[19]36/ F. Lawrence coll. (1, CASC) ; [Tillamook Co.], Boyer, VII-23-[19]41, Fender (2, MCZC) ; [Marion Co.], Woodburn , July-25-1966, Blk Light trap, Kenneth Goeden (1, CASC) . Washington: Jefferson Co., 2 mi N. Queets, VI-26-[19]66, F. G. Andrews (1, CASC [ Fig. 34b ]) . Washington Territory : [no data] (2,

MCZC); [no data]/ [male symbol]/ F. Blanchard collection (1, MCZC).

Figures

Fig. 34. Hemicrepidius palpalis. a) Dorsal habitus, male, b) Pronotum, lateral view. Male genitalia: c) Dorsal view, d) Ventral view. Scale bars: 5 mm (a), 1 mm (b–d).

Fig. 35. Distribution maps of examined Hemicrepidius specimens (blue/gray dots). a) H. pallidipennis, b) H. palpalis.