Rhamphomyia minytus 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 : 137-139

Rhamphomyia minytus Walker, 1849

( Figs 16–20 )

Rhamphomyia minytus Walker, 1849: 502 . Type locality: St. Martin’s Falls [Ogoki], Albany River, Ontario, Canada.

Rhamphomyia agasicles Walker, 1849: 499 . Type locality: St. Martin’s Falls [Ogoki], Albany River, Ontario, Canada. Syn. nov.

Note about synonymy. Rhamphomyia minytus and R. agasicles were described in the same paper by Walker (1849). We consider these names to be subjective synonyms, with the former based on a male and the latter on a female of the same species. Acting as the First Revis- er, we select R. minytus as the senior synonym (Article 24.2.2 of the Code, ICZN 1999).

The shiny scutum, anepisternum and abdomen and the broadened hind tarsomere 1 allowed for the association of the sexes. The illustrations of the male terminalia and hind tarsi by Smith (1971, figs 13, 14) facilitated identifi- cation of additional males specimens and direct examination of the male holotype of R. minytus was un-necessary.

Type material examined. Rhamphomyia agasicles : LECTOTYPE ♀, labelled ( Fig. 18 ): “ Type [green mar- gined circle]”; “ One of Walkers / series so named./ EAW [on reverse side: “ Rhamphomyia / agasicles/ Walk.]”; “ Agasciles ,”; “ St. Martin’s Falls,”; “ LECTO- / TYPE [blue margined circle]; “ Pararhamphomyia [written by Smith]”; “ BMNH (E) #/ 246915”; “NHMUK010210622 [data matrix code]” ( BMNH). The lectotype is in good condition, with the left wing slide mounted (see Smith 1971, pl. 2, fig. 6).

Additional material examined. CANADA. British Columbia: Alaska Hwy, mi 392, Summit Lake , 4500 ft, 2–4.vii.1959, E.E. MacDougall (1 ♀, CNC) ; same locality, 5300 ft, 18.vi.1959, R.E. Leech (1 ♀, CNC) ( Fig. 19 ) ; same locality, 5000 ft, 23.vi.1959, R.E. Leech

(1 ♂, CNC) ( Figs 17, 20 ); same locality, 4500 ft, 23–24. vi.1959, R.E. Leech (1 ♀, CNC) .

Diagnosis. Females of this species are distinguished by the shiny scutum, anepisternum and abdomen; hind femur with short posterodorsal pennate setae; hind tibia with short anteroventral setae; hind tarsomere 1 as broad as apex of hind tibia; wings broad, darkly infuscate with pale base. Males are distinguished by the broad and setose hind tarsomere 1; base of hind tibia with cluster of posterior setae; cercus and epandrium narrow and elongate with base of both shiny.

Redescription. Wing length 3.5–3.8 mm. Male. Head dark in ground-colour, with greyish pruinescence on face, frons, postgena and occiput; oral margin shiny reddish. Holoptic, eyes with ommatidia larger on upper half of eye, smaller on lower half. Frons divergent towards an- tennal sockets, bare. Margins of face slightly divergent; greyish pruinescence laterally, glossy medially. Ocellar triangle shiny with pair of ocellar setae, shorter than postocular setae. Occipital setae posterior to ocellar triangle stouter than postocular setae. Postocular setae long and slender; postgenal setae similar to postoculars. Antenna dark; scape slightly longer than pedicel; postpedicel nearly 3× longer than basal width; stylus length about half length of scape. Palpus dark, slender, bearing several long, subapical setae. Clypeus bare and glossy; labrum dark and glossy, slightly longer than eye height; labellum dark and bearing many dark setae, subequal or longer than palpal setae.

Thorax dark brown with dense grey pruinescence; anepisternum shiny; dorsum of scutum shiny, with anterior face of postpronotal lobe and lateral margin from notopleuron to scutellum and prescutellar depression pruinescent. Prosternum bare; proepisternum at fusion point with prosternum with several setae; upper part of proepisternum in front of anterior spiracle bare. Antepronotum with row of stiff setae. Postpronotal lobe with 1 outstanding seta and several shorter, finer setae; acrostichals biserial, slightly shorter than dorsocentral setae; dorsocentrals biserial to prescutellar depression, increasing in length posteriorly, uniserial prescutellar setae shorter than apical scutellar setae, dorsocentral row curved towards postpronotal lobe anteriorly; 1 presutural supra-alar seta (posthumeral) and several shorter setulae; 3 notopleural setae, with several setulae; 0 prealar setae; 1 postsutural supra-alar seta; 1 postalar seta; 1 long apical pair and short lateral pair of marginal scutellar setae. Laterotergite with cluster of long, dark setae. Anterior and posterior spiracles concolourous with pleura.

Legs dark brown, somewhat shiny. Fore coxa with row of 5–6 stiff anterolateral setae; lateral regions of mid and hind coxae with similar setae. Fore femur with row of fine posteroventral setae. Fore tibia with several rows of dorsal setae, longer than width of tibia; posterior face clothed with fine short setae. Mid femur with an- teroventral and posteroventral rows of stout setae, longer than width of femur. Mid tibia clothed with stout ventral setae, shorter than width of tibia. Hind femur ( Fig. 4E ) slightly twisted medially on apical third; basal half with row of posterior setae, subequal to width of femur; api- cal third with row of posterodorsal setae increasing in length apically. Hind tibia straight, with anterodorsal setae, increasing in length and stouter apically; base of hind tibia with cluster of posterior setae; 1 long seta in posteroapical comb. Hind tarsomere 1 greatly expanded and flattened, broader than tibia ( Fig. 20 ), with dense dorsal setae, longer than width of segment; tarsomeres 2 and 3 somewhat swollen with long dorsal setae.

Wing lightly infuscate; pterostigma elongate, lightly infuscate; without basal costal seta. Cell dm subequal in length to cell bm; CuA+CuP weak, reaching wing margin as crease; alular incision right angled; margin of calypter with brown setae. Halter pale yellowish brown.

Abdomen dark brown, shiny, with longer ventral setae; dorsolateral setae pale brown. Tergite 8 reduced to half-length of sternite; sternite 8 with short rounded posterior margin bearing long setae, longer than length of sclerite. Terminalia ( Fig. 17 ) dark brown (undissected). Epandri- um elongate, slightly constricted beyond middle, bearing many fine setae, longer along ventral margin and apical- ly; middle outer face with dense setae; lower basal half polished. Cercus elongate, 3/4 length of epandrium; expanded beyond mid-length; polished on basal half; dorsal margin at base bearing many short, fine setae; inner sur- face on apical half with numerous slender setae. Phallus filamentous, with slight inward curve towards middle, forming loop extending beyond epandrium and recurved between cerci; ejaculatory apodeme and hypandrium not examined in undissected specimen.

Female. Similar to male except frons shiny with pale lateral setulae, with greyish pruinescence above antennae; hind femur with short posterodorsal pennate setae, hind tibia with short anteroventral setae; hind tarsomere 1 as broad as apex of hind tibia ( Fig. 16 ); wings broader than male, darkly infuscate with pale base ( Fig. 19 ).

Geographical distribution. This species is known from northern British Columbia and northern Ontario ( Canada) .

Remarks. Rhamphomyia minytus is assigned to the R. (Pararhamphomyia) caudata (Zetterstedt, 1838) group, and in North America this species group also includes R. priapulus Loew, 1861 and R. ursinella Melander, 1928 and several undescribed species.

Figures

Figs 16–20. Rhamphomyia minytus Walker. 16. Lectotype of R. agasicles Walker, female, dorsolateral view; 17. Recent specimen, male terminalia, lateral view; 18. Lectotype of R. agasicles Walker, labels, left label underside of corresponding label in centre row; 19. Recent specimen, female, lateral view; 20. Recent specimen, male hind leg, anterior view. See Additional material examined section for locality details of recent specimens.

Figs 1–5. Rhamphomyia cophas Walker. 1. Holotype, female, dorsal view; 2. Holotype labels; 3. Holotype, lateral view; 4. Recent specimen, female, lateral view; 5. Male terminalia, lateral view. See Additional material examined section for locality details of recent specimens.