Large green and brown bee - Pasadena, CA

very astute observation; I see it comes from someone who knows these. Lichnanthe apina does occur in the San Gabriels, incl. Pasadena area.
A couple of specimen photos can be seen at Calphotos, though the metallic green may vary to somewhat darker.

I have a problem with the adult activity cited and overall dimensions in concluding Lichnanthe. Also, Lichnanthe do not construct a nest of sorts.

Lichnanthe are smaller (0.75-inches) and are often associated with sandy habitats, for example riparian zones or washes, or coastal dunes.

Further more, the described coloration, and again, adult activity does not correlate to any species of California Areodina (Cotalpa and it's relatives) and all species are terrestrial with larvae feeding on rotting wood pulp or plant rootlets in the soil.

... Hymenoptera I suspect.

but size estimates from some distance could be off. I don't know where James saw this, but there are houses close enough to the mountains & washes to attract all sorts of things. Other than carpenter bees, already mentioned (though not exactly fitting the description), I can't think of anything in Hymenoptera in our area that would fit.
Perhaps James will revisit this? Also, he doesn't say that he has observed an actual nest, or nesting activity. Perhaps we're just tapping around in the dark?

> Perhaps we're just tapping around in the dark?

More like the past. But it was fun to read as I lived a good number of years in Pasadena, not too far down the road from the Eaton Canyon Nature Center.

-K

still going by your description, but Paracotalpa adults come out in springtime (same for Cotalpa see also Evans & Hogue (1)), though two spp. of the four known from CA roughly fit the color description. Distribution is another matter, and I'm not sure whether they live here in the foothills.
Three spp. of Carpenter bees in our area, of which only Xylocopa varipuncta , and X. californica diamesa come close to an inch in length. Only the latter looks at all metallic; the Valley Carpenter bee looks black in flight, the males are light brown with blondish hair.
I suppose you can take a look at those.
The Green Fruit Beetle (Cotinis mutabilis), which my wife & I have found in our garden - also flying onto our deck - is about right in size, and metallic green.
I'm not sure whether this is helpful, but at least its something to look at.

This sounds much more like a beetle to me, actually, specifically one of the scarab beetles in the genus Paracotalpa or Cotalpa. Please check the guide pages for those two genera, and see if it doesn't match what you are seeing. The behavior seems odd, but the description definitely fits Paracotalpa.

I checked those and they do seem to be close. However, I do not see any wing cases when it is flying, as you would expect to see with a beetle.
Certainly some of the colors and the size range would be similar to those beetles you mention.

I just saw it again this morning, although briefly, and it still looks more like a large bee. It was moving fairly quickly this time and was difficult to really see detail.

I'll try to get better descriptive detail if I see it again.

James Goss

Interesting, I know of no bees fitting this description in the Pasadena area. A bit early for Cotinis though or so it seems.

another beetle genus, Lichnanthe, which seems to me a plausible explanation of what James Goss saw. I think that Lichnanthe apina may be a good candidate.