Rhamphomyia mallos Walker, 1849

Sinclair, Bradley J. & Saigusa, Toyohei, 2018, Revision of Francis Walker’s female types of North American Rhamphomyia Meigen (Diptera: Empididae), Bonn zoological Bulletin 67 (2), pp. 129-143 : 136

Rhamphomyia mallos Walker, 1849

( Figs 11–15 )

Rhamphomyia mallos Walker, 1849: 502 . Type locality: St. Martin’s Falls [Ogoki], Albany River , Ontario, Can- ada.

Type material examined. Rhamphomyia mallos : HOLOTYPE ♀, labelled ( Fig. 13 ): “Type [green margined circle]”; “44/ ?? [underside: Hudson’s/ Bay]”; “ One of Walkers / series so named./ EAW [on reverse side: “ Rhamphomyia / mallos/ Walk.]”; “Mallos ,”; “St. Mar- tin’s Falls,”; “s.g./ Pararhamphomyia / det. K.G.V. Smith, 1966”; “ Holo- / type [red margined circle]; “ BMNH (E) #/ 246922”; “NHMUK010210625 [data matrix code]” ( BMNH) . Holotype is missing the left foreleg, fore tibia and tarsi and left hind tarsomere 2–5; the left wing is slide mounted (see Smith 1971, pl. 3, fig. 2).

Diagnosis. The holotype female is characterized by pale legs, bare prosternum, pennate setae on mid- and hindlegs and thickened setae dorsally on fore femur; postpedicel short, rounded basally; abdomen with pennate setae laterally on segments 3 and 4 (on pleura?).

Redescription. Wing length 7.3 mm. Female. Head dark in ground-colour, with greyish pruinescence on face, frons, postgena and occiput; oral margin pruinescent. Dichoptic, ommatidia with uppermost smaller. Frons and face broad, subequal in width; frons with row of setulae along eye margin, uppermost shorter. Ocellar triangle with pair of ocellar setae. Upper half of occiput bearing row of stout postocular setae; lower postocular setae slender and shorter. Occipital setae black and stout; postgenal setae long and slender. Antenna ( Fig. 12 ) with scape and pedicel pale brown, postpedicel darker; scape 1.5 times longer than pedicel; postpedicel with broad base, 4 times longer than pedicel; stylus greater than half length of postpedicel. Palpus yellowish brown, slender, bearing numerous long, dark setae. Clypeus not visible; labrum dark and glossy, nearly 1.3 times longer than eye height ( Fig. 11 ); labellum dark and bearing many long, dark setae.

Thorax dark with dense grey pruinescence; brownish vittae beneath acrostichal and dorsocentral rows; lateral scutum with apparent brownish ring encircling base of major setae; posterior corner of postpronotal lobe and postalar ridge brownish. Prosternum bare; proepisternum at fusion point with prosternum with 3 long, slender setae; upper part of proepisternum in front of anterior spiracle bare. Antepronotum with row of stout setae. Postpronotal lobe with 1 outstanding seta, clothed in numerous long and short, slender setae; acrostichal setae biserial, subequal in length to dorsocentral setae; dorsocentral setae uniserial, biserial anteriorly, prescutellar seta subequal in length to scutellar setae; dorsocentral row curved towards postpronotal lobe anteriorly; 3 presutural supra-alar setae (posthumeral) and 2 posterior presutural supra-alar setae; 4–5 anterior notopleural setae and 3 posterior notopleural setae in oblique row; 3–4 prealar setae; 1 postsutural su- pra-alar setae; 1 postalar seta; 2 pairs of marginal scutellar setae. Laterotergite with cluster of long, dark setae. Anterior and posterior spiracles yellowish brown, concolourous with halter.

Legs long, pale or yellowish brown with very thin grey pruinescence on coxae. Fore coxa with row of long slen- der anterolateral setae; lateral region of mid and hind coxae with similar setae. Fore femur with row of anteroven- tral and posteroventral setae; stronger anterodorsal setae on basal third. Fore tibia lost. Mid femur with antero- ventral row of short, even-length setae, longer near base; posteroventral row of pennate setae nearly half length of femur width; anterodorsal setae narrowly pennate, slightly shorter than setae of posteroventral row. Mid tibia with anterodorsal and posteroventral row of pennate setae; row of anteroventral setae short. Hind femur with row of anterodorsal and posteroventral pennate setae ( Fig. 15 ); setae of anteroventral row short and slender. Hind tibia with row of anterodorsal and posteroventral pennate setae, shorter than width of tibia; 5–6 posterodorsal setae; 1 long seta in posteroapical comb. Tarsomere 1 of all legs without pennate setae.

Wing infuscate, especially along veins ( Fig. 14 ); pterostigma elongate, distinct; basal costal seta absent. Cell dm slightly shorter than length of cell bm; CuA+CuP reaching wing margin with weakening at mid-length; alular incision nearly right angled; calypter with dark setae. Halter yellowish brown.

Abdomen dark brown with black setae; pennate setae laterally on segments 3 and 4. Cercus long and slender, with fine setae.

Male. Unknown.

Geographic distribution. The label data is likely incorrect (see Remarks) and this species is possibly found in southeastern North America.

Remarks. Rhamphomyia mallos initially appeared very similar to R. (Dasyrhamphomyia) villipes Coquillett, 1900 on the basis of pennate setae on legs and large size, but the latter species has more setae on the fore femur, proboscis distinctly longer, postpedicel elongate and without abdominal pennate setae. No specimens could be found that matched the distinctive combination of features of this female, especially the abdominal pennate setae. It is doubtful such a large sized species from northern Ontario would be absent from the CNC, which could indicate that the specimen is mislabelled and possibly originates from the southeastern United States of America. Expanding the search, we found that R. mallos is rather similar to R. testacea Loew, 1862 , with reduced setae on the fore femur and broad postpedicel, but the length of the pennate setae of the latter species is longer than the width of corresponding leg segment (see MCZ type collection: http://140.247.96.247/mcz/Species_record. php?id=13637). There is also an undescribed brownish species in the CNC from Virginia, Tennessee, Arkansas and possibly Mississippi and Texas, where the females possess abdominal pennate setae, very similar shaped postpedicel and very long pennate setae on all legs. The latter species is currently assigned to a group of species similar to R. pectinata Loew, 1861 . Unfortunately all these species differ from R. mallos in antennal colour, thoracic chaetotaxy and length of the pennate setae on the legs.

Figures

Figs 11–15. Rhamphomyia mallos Walker. 11. Holotype, female, fore femur, head, lateral view; 12. Holotype, antenna, head, anterior view; 13. Holotype labels, left two labels underside of corresponding labels in centre row; 14. Holotype, lateral view; 15. Hind leg, posterior view.