Euchariomyia Bigot

Evenhuis, Neal L. & Gang, Yao, 2016, Review of the Oriental and Palaearctic bee fly genus Euchariomyia Bigot (Diptera: Bombyliidae: Bombyliinae), Zootaxa 4205 (3), pp. 211-225 : 213-214

Genus Euchariomyia Bigot

Euchariomyia Bigot, 1888a : cxl. Type species: Euchariomyia dives Bigot, 1888 , by monotypy.

Eucharimyia Bigot in Mik, 1888: 331 [ Bigot 1888b: cxlvii] (unjustified emendation of Euchariomyia Bigot, 1888a ).

Eucharimyia Bigot, 1889 : cxl [as “ Euchariomyia ” on pp. ccliii, cclxx]. Type species: Euchariomyia dives Bigot, 1889 [= Euchariomyia dives Bigot, 1888 ], by monotypy. [Preoccupied by Euchariomyia dives Bigot, 1888 .]

Comastes: Wulp 1885: 85 ; Bigot 1892: 162; Wulp 1896: 74; Brunetti 1909a: 457 (misidentification).

Greathead (1995) was the last to review the genera allied to Bombylius (= his “ Bombyliini ”) and provided a key to genera, but excluded Euchariomyia as it was not within the geographical scope of the paper. Using the key in Greathead & Evenhuis (2001), Euchariomyia runs to Bombylella Greathead. Both are similar in appearance based on the prominent silvery patches of tomentum on the head, thorax and abdomen. Additionally, both also lack hairs on the anepimeron (present in Bombylius and many African and Eurasian genera allied to Bombylius ) and both possess a cell r5 closed at the wing margin by a long stalk (this cell open in the wing margin in Bombylisoma Rondani (another genus with prominent silvery patches that may be confused with Euchariomyia ). Although Greathead (1995) did not key out Euchariomyia , he provided characters for it in his phylogenetic analysis that can be used to distinguish Bombylella from Euchariomyia . In that analysis Euchariomyia was sister to the remainder of the “ Bombylius ”-like genera and Greathead concluded that Euchariomyia could thus not be maintained within the Bombyliini . A recheck of those characters in Greathead (1995) show that unfortunately some were incorrectly coded, which if reanalyzed may show a different placement of Euchariomyia relative to those genera.

We have re-examined the characters given by Greathead (1995) and the following can be used as a diagnosis in distinguishing Euchariomyia from Bombylella as well as many other bombyliine genera with a closed cell r5: face bare medially, shining (densely hairy medially and laterally and dull-colored in Bombylella ); head as wide as thorax (narrower than thorax in Bombylella ) [but this is only because the thorax is narrow in Euchariomyia , not that the head is wider than in Bombylella ]; eyes in male holoptic for more than length of ocellar tubercle (length of holopticism subequal to or shorter than length of ocellar tubercle in Bombylella ); thorax and abdomen slender, approximately the same width [thorax broad and abdomen (much broader than thorax) chordate in dorsal view in Bombylella ]; costal hook not developed (well developed in Bombylella ).

It is useful to also discuss here the characters that Greathead (1995) erred in coding, in order to assist future workers interested in the taxonomy or systematics of these genera. Greathead (1995) listed the following character states(using his morphological terminology in quotes with current equivalents) in his character matrix for phylogenetic analysis as distinguishing Bombylella and Euchariomyia , but these have not been borne out in our investigation:

1. Posterior margin of eyes indented vs entire—both Euchariomyia (to a lesser degree) and Bombylella (to a greater degree) have a wavy indentation of the posterior eye margin (best seen at left on Fig. 9 for Euchariomyia ); Greathead (1995) coded this in reverse with Euchariomyia as having the indentation and Bombylella as not having an indentation. [Greathead character 32].

2. Scape length less than vs more than 3 times length of pedicel—both Euchariomyia and Bombylella vary slightly in having the length of the scape from between 2. 5–4 times the length of the pedicel; Greathead (1995) coded this character as Euchariomyia having the scape less than 3 times the length of the pedicel and Bombylella as more than 3 times the length. [Greathead character 8].

3. “Metapleuron”[= laterotergite; the sclerite immediately in front of the posterior spiracle] hairy vs bare—both Euchariomyia and Bombylella have a patch of hair or scale-like hairs on this sclerite; Greathead (1995) coded this as Bombylella having hairs on this sclerite and Euchariomyia as having this sclerite bare. [Greathead character 12].

4. Scutellar macrochaetae well developed vs hairlike—both Bombylella and Euchariomyia have thickened bristles (macrochaetae) on the posterior margin of the scutellum. In the case of Euchariomyia , we have seen specimens in this study with these hairs not appreciably thickened, but there are others that are distinctly bristlelike; Greathead coded this character as Bombylella having scutellar macrochaetae and Euchariomyia as not having them. [Greathead character 13].

5. “Crossvein m-m” [= crossvein dm-cu; the crossvein closing the discal cell] shorter than vs as long as or longer than crossvein r-m; Euchariomyia consistently has these two crossveins subequal in length, but Bombylella varies with some species having a very short crossvein dm-cu while other species have both crossveins subequal in length; Greathead (1995) coded Euchariomyia correctly as having these two veins subequal but coded Bombylella as having crossvein dm-cu shorter. [Greathead character 18].

6. Alula longer than wide vs alula wider than long—both Bombylella and Euchariomyia have an alula that is wider than long and very prominent [the key in Greathead & Evenhuis (2001) indicated the alula to even be reduced and narrow in Bombylella which we could not verify in species we studied]; Greathead (1995) coded Euchariomyia as having the alula longer than wide and Bombylella as having the alula wider than long. [Greathead character 20].

7. Squama well developed vs vestigial—both Bombylella and Euchariomyia have the squama well developed with a sclerotized posterior margin. The squama in Euchariomyia is not as large as in Bombylella but it is clearly not reduced or vestigial; Greathead (1995) coded Bombylella correctly as having a well developed squama but incorrectly coded Euchariomyia as having a reduced or vestigial one. [Greathead character 21].

8. Gonostyli narrow and pointed vs “otherwise”— both Bombylella and Euchariomyia have the gonostyli distinctly narrow, tapered and culminating in a pointed apex; Greathead (1995) coded Bombylella as having such gonostyli and Euchariomyia as not. [Greathead character 29].

Figures

FIGURES 8 – 9. Euchariomyia dives Bigot, male thoraces, lateral view. 8. “ Typical ” Sri Lankan specimen showing orange vestiture; 9. Atypical Sri Lankan specimen showing black vestiture.