Moved from Vermileo.

From the existing keys in Leonard(1930) and Pechuman(1938)...I guess the brownish tint of the wings in your photos would take this to V. comstocki. That's also consistent with its close proximity to the Donner Pass record of Powell for V. comstocki mentioned on pg. 148 of Cole & Schlinger(1)(1965).

However, the (tiny) palpi (visible above the yellowish proboscis) don't look particularly black to me...more brownish-yellow, which would suggest V. opacus (see the remarks below).

But as I mentioned under James' post below:

 

....I'm seriously wondering whether V. comstocki and V. opacus are truly distinct species...or whether they may constitute a single somewhat variable biological species?
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I just gave the various references a more thorough reading...and I think both species were initially described from very few specimens (maybe a single one?), as was fairly common up to the early 1900's.

For instance, in Coquillett's 1904 original description of Pheneus opacus (=Vermileo opacus), it appears he worked from a single male. He described the proboscis as "yellow" (he made no explicit mention of the palpi).

And although Wheeler(1918) mentioned collecting "about 200 larvae" from his Alta Meadow type-locality for V. comstocki...he only explicitly mentioned rearing one adult female successfully, and his detailed description treats the female only. He described the palpi as "black", and the proboscis as "pinkish".

Leonard(1930) treated both nearctic species of Vermileo, giving a key and detailed description & commentary.

For V. comstocki, Leonard's treatment was based on Wheeler's description of the female and 2 paratypes ("in rather poor condition"), loaned to him be Wheeler. Presumably one of those two paratypes was a male...since his description of the males was simply: "Not noticeably different from the female in size, structure, or markings". He described the female as having "palpi blackish, proboscis brownish yellow".

In his discussion of Pheneus (=Vermileo) opacus, Leonard stated (on pg. 73) that only 3 male specimens were known at that time...the type collected in Ormsby Co., NV; and 2 from Alamogordo, NM. He described the type as having "palpi small, dark brown" and "proboscis yellowish brown"...while the Alamogordo specimens had "proboscis, palpi, and front legs pale yellowish".

Finally, Pechuman(1938), based on 1 female and 9 males from two localities, described V. opacus as having "palpi and proboscis pale brownish yellow". He provided a clear discussion of the nomenclatural history for V. opacus up to the time, and indicated that Wheeler was later inclined to believe his V. comstocki was a variety or synonym of V. opacus (which he was unaware of when he published in 1918...and it went under the name of Pheneus opacus). Pechuman, however, believed opacus and comstocki were indeed distinct, and separable by the characters given in his key...which involve distinctions of color & stripes on the thorax, and tint of the wings that, to me, seem fairly subtle and not clearly compelling as a basis for separating two species. (He doesn't mention color of palpi in his key.)

Of course, I certainly don't have the expertise or experience to settle anything here...but it all makes me wonder. That's why I think that with more and more distribution info available, and presumably more specimens, it would be interesting to thoroughly scrutinize the synonymy question...paying close attention to how specimens actually reconcile with the detailed descriptions of Coquillett, Wheeler, Leonard, and Pechuman.

As an aside, from an admittedly very preliminary exploration, it seems there may be lingering questions about synonymy for the Old World species too (i.e. V. degeeri, V. balearicus, and V. niloticus).

As with so many groups, this genus seems to be ripe for a revision!

(I've often thought that a massive, concerted international effort to address the unresolved problems in taxonomy and systematics (à la the "space program" of the 60's) would be a great way to eliminate the world unemployment problem! :-)