Here is a bee you identified for us in 2018 as Triepeolus rufoclypeus. Most of the Triepeolus bees we see in Hidalgo County look like this one.
A female Triepeolus rufoclypeus
This looks like Triepeolus lunatus to me. There were many of these feeding on Solidago last fall at the National Butterfly Center. Notably, however, the usual host of T. lunatus -- Melissodes bimaculatus - does not seem to be endemic to the Lower Rio Grande Valley. In the 2+ years we've been documenting bees there, we haven't seen a single one. We saw many M. bimaculatus when we were in Austin (here in Florida, they are ubiquitous), so we've actively kept an eye out for them in Hidalgo County, without results. Could Triepeolus lunatus have an alternative host? The most common long-horned bees at the NBC in the fall are M. tepaneca and Melissoptila otomita.
Male Colletes swenki?
Size: 7-8 mm (male)
Downy Ground Cherry
March 5, 2020
detailed photos of male bee
This is a small (7 mm) male Colletes bee found on Physalis.
Below is a female Colletes swenki found during April 2019, in the same area, on purple ground cherry (Quincula lobata). The female was larger -- 11 mm.
This is one of the female Colletes bees we found feeding on t he same seaside goldenrod plants as the male bee you identified as Colletes birkmanni. All of the female Colletes bees we're seeing on the goldenrod have the same rust-colored thorax hairs. (The female Colletes birkmanni identified last year also had this trait.) The females lack the specialized sternum hairs found on the male bee. (Photos of last year's female and of this year's male are shown below the latest photos of this new female.)
Size: 12 mm (female)
8-10 mm (male)
Associated plants at NBC:
Plant Family: Asteraceae
Female bee found a year ago, in November 2018
Male bee found a week ago, in October 2018
Confirmed ID Requests
ID's have been confirmed for the species below
Perdita female and male
Size: 8 mm (female)
Detailed photos of female bee
This is a fairly large female Perdita - around 8 mm. There were dozens of these feeding on cowpen daisy. The bands on the female bee's abdomen are broad, bright yellow and uninterrupted. Its thorax is metallic bronze with a yellow spot on each pronotal lobe and a narrowly interrupted stripe on the pronotal collar. The the top half of the face, above the antennae, is dark. The clypeus is dark, with yellow markings. The bees' jaws bend at sharp right angles; the jaws are mostly red, and black at the tips. The wing veins are pale, including the stigma. I was wondering if this might be Perdita (Cockerellia) verbesinae?
Perdita (Cockerellia) male
Size: 8 mm (female)
(male is also 8 mm)
The 8 mm male bee shown here was found with the female shown above. The male bee lacks abdominal bands. The apical rims of its terga are lined with sparse pale hairs. The bee's thorax is metallic bronze with a narrowly interrupted stripe on the pronotal collar. The the top half of the face, above the antennae, is dark. The clypeus is dark, with yellow markings. The bees' jaws are orange. The wing veins are very pale, including the stigma. Despite the lack of yellow bands, I was wondering if this might be the same species as that above? I read in Timberlake that Perdita (Cockerellia) verbesinae sometimes appears without bands? Or are the jaws of the male bee too different from those of the above female for them to be the same species?
Size: 6 mm (female)
Food plants at NBC:
Golden prickly poppy
(Argemone aenae texana)
This is the male bee you identified for us last year as Ceratina texana.
Is this a male Osmia subfasciata? We saw many female Osmia subfasciata in the same area in March and April last year.
There are many male Osmia bees like the one below at the National Butterfly Center right now, feeding on vetch and Texas baby bonnet.