---

I think I’ve got this one keyed out to be a male Hebecnema using the key in the Manual of the Nearctic Diptera but I’d appreciate some expert input. Thanks in advance for the help.

body length: ~4mm
environment: semi-urban, treed office park w/a small stream and pond in Maryland, USA

Larger and higher resolution images on my Flickr site

---

lateral view

---

ventral

---

head-on

---

poor photo but shows detail of posterior thorax

---

detail of setal pattern on 1st abdominal sternite (from a poor stack)

---

I think that Hebecnema is correct. have you tried keying it to vespertina?

---

Thanks John and Nini. I've looked at a 1921 key by Malloch on the North America species in this genus. This fly could be H. vespertina but the key says that the abdomen should have a "very distinct dorsocentral vitta" . There's a vitta of sorts on the abdomen but I'm not sure I'd call it "very distinct"

---

Hebecnema can be difficult to id because all of the available material describes certain features differemtly. I've checked Hennig, then Gregor and Rozkosny for a description. Neither publications stress a male vitta as being very distinct. To quote the material: "Abdomen with a short black midline (often absent on tergite 4)." The femora are darek and the knob of the haltere is dark. I think that vespertina is a good match.

Maybe someone else has a better suggestion. I'm certainly not a Muscidae expert. I have a little experience with Hebecnema.

can you see pd bristles on the mid tibia? how many do you see?

---

Here's a photo of the mesotibia. Whatever little experience you may have with Hebecnema, it’s more than I have – this is the first one I’ve seen so getting the ID to genus is still progress. I have another that won't upload directly so I'll put it on my Flickr site and use the [img] tag

Thanks again for the help

Steve

anterior is to the left in this one

---

here's another with anterior to the right this time. I looked at your post on Hebecnema nigra and the page you provided a link to on"Hebecnema Confusion". It's seems like the taxonomy of this genus needs some serious work

---

we can use the art of deduction here. Thus, let us briefly describe your subject:
eyes appear to be sparsely haired. parafacials silvery. one av hind tibia. two pd mid tibia. femora are dark at all angles. all tibiae are reddish yellow at certain angles but can be described as obscure. abdomen has a dark midline.

specimen is not H. umbratica.
H. umbratica has hairy eyes. male eyes are touching. parafacials are silvery white. legs are entirely black.

specimen is not H. fulva.
H. fulva is supposed to be entirely yellow.

specimen is not H. pallipes.
H. pallipes has all femora and tibiae reddish yellow.

specimen is not H. nigricolor
H. nigricolor has mid and hind femora reddish yellow in addition to all tibiae being reddish yellow.
eyes are bare, parafacialia are not silvery. halteres yellow. male calypters have a brownish yellow rim.

specimen is not H. fumosa
parafacials are supposed to be brown and it is supposed to be missing the dark midline on the abdomen
description of legs matches but overall this isn't a match.

we are left with H. vespertina.
eyes with short sparse hairs? yes
calypters yellowish? yes.
haltere with yellowish base and dark knob? yes
hind tibia with one av? yes
abdomen with a dark midline? yes
wings infuscated on male? yes
parafacials brown? not exactly but at certain angles they appear to be brown.

I think that this is H. vespertina.
If anyone has a different opinion, then eventually that someone will post here.

we should call it Hebecnema cf vespertina without genitalia or an expert opinion.

I hope that you have a Pleasant Day.

---

Thanks, that seems quite reasonable. I've changed the title of the post to match. I hope you have a pleasant day too.