American hoverfly (Eupeodes americanus)? - Eupeodes

Moved

Moved from American Hover Fly.

According to Vockeroth 1992, the way to separate out male americanus, pomus, and fumipennis is using the features of the male genitalia; fumipennis is western (WA/CA/NV), the other two widespread. Females of all 3 species all fall out in the same couplet and cannot be separated in his key.

Obviously this group (americanus/pomus) is fine because we can put eastern specimens here, but western specimens may need to go in a unified americanus/fumipennis/pomus group.

… Kelsey J.R.P. Byers, 23 October, 2019 - 5:25am

Martin has done a lot work wi

Martin has done a lot work with fumipennis and it is westwern and sufficientlly different to be separated. We are happy with the fumipennis identifications.

… Bill Dean, 23 October, 2019 - 7:19am

Great! A relief to hear.

… Kelsey J.R.P. Byers, 23 October, 2019 - 7:34am

You are right. I think this s

You are right. I think this should go in Eupeodes americanus/pomus group to be certain.

… Bill Dean, 23 October, 2019 - 4:40am

How was this separated from E. pomus?

How was this separated from E. pomus? From what i've heard americanus and pomus can only be distinguished from each other by examining the surstyli on male flies. I would be greatly interested in how to identify them otherwise.

… Oliver Burrus, 22 October, 2019 - 8:57pm

Moved

Moved from subgenus Metasyrphus.

… Kelsey J.R.P. Byers, 18 October, 2016 - 4:37pm

Eupeodes americanus ...... fe

Eupeodes americanus ...... female, I would say.
The Eupeodes are variable and Eupeodes americanus is no exception.
The bands on tergite three and four are more wavy on fumipennis and it is western. There are some Eupeodes americanus which are difficult to tell apart from related species but some if the bands are wide and straight on anterior and posterior margins, the males with yellow frons and any marks above antennae very very restricted and females with the front of frons broadly yellow, tergite 5 with black sides and yellow tip in both sexes, then they are likely Eupeodes americanus. There are some Eupeodes americanus which are difficult to tell apart and indistinguishable but if they have the above features I would place them in Eupeodes americanus.

… Bill Dean, 18 October, 2016 - 4:07pm

Thanks for the additional inf

Thanks for the additional info. I'm not sure I can accurately identify these myself, and probably should leave it to the experts.

Yesterday I saw another one of these (I think) that was pretty slow moving. I was able to get much better pictures and more angles. Are the best angles for identification of these the face, the end of the abdomen, and a dorsal and lateral view of the whole fly?

… molanic, 20 October, 2016 - 5:04pm

For me, the most important vi

For me, the most important views for hoverflies are (in general order) a dorsal view of the entire fly holding still (so wing veination visible), a view of the side of the abdomen and thorax and ideally the head, a view showing the leg coloration if not shown already, a view of the face including the forehead/frons, and a view of the bottom of the fly. End of the abdomen is less important, though some species keys do use it. Hope that helps!

… Kelsey J.R.P. Byers, 20 October, 2016 - 6:32pm

Thanks for the quite detailed

Thanks for the quite detailed explanation!!

… Kelsey J.R.P. Byers, 18 October, 2016 - 4:38pm

Moved

Moved from Syrphid Flies.

Eupeodes (Metasyrphus) are generally quite hard to get to species from photos, it generally seems to require details of the hairs on the wings and genitalia for the males, while many of the female species cannot be reliably distinguished unless in copula with a male.

I've seen a lot of IDs to Eupeodes americanus which I'm frankly skeptical of - Vockeroth notes in his 1992 book that the females are "not distinguishable from those of E. fumipennis and E. pomus" and he uses details of the genitalia to distinguish the males - and the range of E. americanus overlaps with both of these other two species, so it's no help either.

… Kelsey J.R.P. Byers, 16 October, 2016 - 1:25pm

Thanks for the help. It's alw

Thanks for the help. It's always confusing when I see a quote saying they cannot be identified to species from photos, but then see that being done referencing key markings. I never know if that is just from information not being updated, or an actual disagreement on that information. Thanks for the ids on the other two flies I posted also.

… molanic, 18 October, 2016 - 10:04am

It is by comparison to positi

It is by comparison to positive identifications that show features or combination of features not found in the other related species. When species are variable, some variables are difficult to tell apart. Also distribution often helps.

… Bill Dean, 20 October, 2016 - 5:09pm