The male and female Andrenas below were mating shortly before captured.  They were two of hundreds of similar Andrena bees feeding on two large cenizo shrubs at Falcon Park.

Andrena - male
Unnamed cenizo specialist

Size:  7.5 mm (male) 

Associated plant:

Cenizo (Leucophyllum frutescens )

Plant family: Scrophulariaceae 

When seen: May 26, 2021
Falcon State Park
Starr County

Male bee -- This is a moderately-small, narrow-bodied Andrena with uninterrupted white hair bands on its abodmen.

Dorsal view of bee

Face of bee

Alternate view of male bee

Dorsal view of abdomen

WJPEG-Andrena-M-NBC-#396-Cenizo-Falcon-P

male bee

Andrena - female
Unnamed cenizo specialist 8 mm (female) 

Associated plant:

Cenizo (Leucophyllum frutescens )

Plant family: Scrophulariaceae 

When seen: May 26, 2021
Falcon State Park
Starr County

Female bee

lateral view

dorsal view of abdomen

male bee

Protoandrena (Pseudopnurgus) texana

Size:  7.5 mm (female) 

Associated plant:

Sweet-stem (Aloysia macrostachya )

Plant family: Verbenaceae 

When seen: May 26, 2021
Falcon State Park
Starr County

Female bee

Dorsal view

Vertex and front of scutum

Lateral view

Rear view

female bee