Hemipenthes Loew

Ávalos-Hernández, Omar, 2009, A review of the North American species of Hemipenthes Loew, 1869 (Diptera: Bombyliidae), Zootaxa 2074, pp. 1-49 : 3-7

Hemipenthes Loew

Hemipenthes Loew, 1869: 27 . Type species: Musca morio Linnaeus, 1758 , by subsequent designation (Bezzi, 1908: 31). Isopenthes Osten Sacken, 1886a: 96 . Type species Isopenthes jaennickeana Osten Sacken, 1886 , by subsequent designation ( Coquillett, 1910: 556).

Diagnosis. Body length 5–14 mm. Basal half, more than half or whole wing dark, sepia brown of blackish; color is sharply defined, diagonal or oblique, either with irregular steplike edge or smooth, and often extending no farther backward than the end of the r4 cell. Face either rounded and retreating or at most blunt and vertical, face and front covered with erect stiff pile. Flagellomere onion-shaped at base, rather abruptly narrowed with long, fine style. Anterior tibia smooth, without spines or just with a single row of black bristles on postero-ventral surface. Discal cell with a wide, obtuse ending.

Historical remarks. In 1758 Linnaeus described the genus Bombylius . He also described some species of Bombyliidae under the genus Musca , one of this was M. morio Linnaeus ( Hull, 1973) . In 1763 Scopoli excluded M. morio from Musca and placed it in his new genus Anthrax . The distinctive character of Anthrax is a tuft of hairs at the tip of flagellomere. Scopoli thought that the specimens he used to describe Anthrax were from M. morio , but they were misidentified and in fact belonged to Musca anthrax Schrank. This misidentification was not known until the mid-20th century ( Hull, 1973).

Musca anthrax and M. morio , among other bombyliids species described by Linnaeus, were first placed in a new family called Anthracidae, then moved to Bombyliidae because of the similarity with the species of Bombylius ( Hull, 1973) .

After the description of A. morio , most of the species of the current genus Hemipenthes were described under the genus Anthrax . In 1869 Loew created the genus Hemipenthes for the European species Musca morio and the American species H. seminigra Loew , he considered H. morio as the genus type species. Loew justified the creation of a new genus by the presence of the pulvilli in these two species. But Loew did not consider that A. morio was also the type species for the genus Anthrax , by then it was unknown the mistake made by Scopoli. Osten Sacken (1886b) realized that both genera were described using the same type species, which made Hemipenthes a synonym of Anthrax . Osten Sacken (1886b) placed the species of Hemipenthes under the subgenus Anthrax in the genus Anthrax . Osten Sacken (1886b) also remarked that the presence of pulvilli was not exclusive of Hemipenthes because other species of Anthrax also presented this structure.

FIGURES 1–10. Wings: 1, Hemipenthes albus ; 2, H. bigradata ; 3, H. blanchardiana ; 4, H. castanipes ; 5, H. celeris (light-pigmented wing variation); 6, H. celeris (dark-pigmented wing variation); 7, H. chimaera ; 8, H. comanche ; 9, H. curta ; 10, H. edwardsii .

FIGURES 11–20. Wings: 11, Hemipenthes incisiva ; 12, H. inops ; 13, H. jaennickeana ; 14, H. lepidota ; 15, H. martinorum ; 16, H. morio (Paleartic species); 17, H. morioides ; 18, H. pleuralis ; 19, H. pullata ; 20, H. scylla .

In the Biologia Centrali-Americana Osten Sacken (1886a) proposed the name Isopenthes for I. jaennickeana Osten Sacken and I. blanchardiana Osten Sacken. Osten Sacken observed that these two species were very similar to Anthrax sinuosa Wiedemann but stated that they could be distinguished by the presence of a crossvein between R4 and R2+3, not present in the rest of the Anthrax species.

FIGURES 21–26. Wings: 21, Hemipenthes seminigra ; 22, H. sinuosa ; 23, H. translucens ; 24, H. webberi ; 25, H. wilcoxi ; 26, Chrysanthrax yaqui ..

The same way Osten Sacken (1886b) criticized the validation of Hemipenthes by the presence of pulvilli, Coquillett (1886, 1894a) rejected the creation of Osten Sacken’s new genus Isopenthes , distinguishable by the presence of three a crossvein between R4 and R2+3. Coquillett asserted that this character was not enough to separate genera because some specimens of Anthrax have a crossvein between R4 and R2+3.

Even when Coquillett did not accept Isopenthes as valid, he accepted the genus Hemipenthes defined by the presence of pulvilli, as part of the subfamily Anthracinae ( Coquillett, 1886; 1887) including H. morioides Say , H. seminigra , and H. sinuosa . But he still continued to consider some species of Hemipenthes as belonging to Anthrax , because of the lack of pulvilli ( Anthrax bigradatus Loew , A. celer Wiedemann , A. curtus Loew , A. edwardsii Coquillett , A. floridiana Macquart , A. inops Coquillett , A. lepidotus Osten Sacken , A. sagatus Loew ) ( Coquillett, 1887; 1892; 1894b). By the end of the 19th century Coquillett (1894a) realized that Scopoli and Loew had used the same type species to describe their respective genera and accepted the synonymy between Hemipenthes and Anthrax .

In the beginning of the 20th century, Bezzi found out that the specimens used by Scopoli to describe the genus Anthrax really belonged to Musca anthrax and not to M. morio ( Hull, 1973) . This made Hemipenthes a valid genus with H. morio as its type species. Nevertheless Hemipenthes continued to be considered an invalid name.

Coquillett (1910) presented Isopenthes and Hemipenthes as synonyms of Villa Lioy. Later , other authors ( Johnson, 1919; Painter, 1933; Painter & Painter, 1962; Painter & Hall, 1960) changed the corresponding species from Anthrax to Hemipenthes and placed Hemipenthes as a subgenus of Villa . Both species of Isopenthes ( I. jaennickeana and I. blanchardiana ) were considered as subspecies of H. sinuosa ; and Isopenthes became a synonym of Hemipenthes , the treatment of which is still followed ( Painter & Hall, 1960; Painter et al., 1978). Recently ( Evenhuis & Greathead (1999), H. jaennickeana and H. blanchardiana have been treated separately from H. sinuosa , which is followed here.

Hull (1973) considered Hemipenthes as a valid genus in the subfamily Exoprosopinae and tribe Villini , eliminating all subgenera. Hall (1975) and Painter et al. (1978) however, still published papers using subgenera. The classification followed in this paper is the cladistic analysis of the subfamilies of Bombyliidae ( Yeates, 1994) in which Hemipenthes is placed in the subfamily Anthracinae and the tribe Villini .