This is a medium-small, robustly-built pale bee with appressed beige hairs covering its abdomen and faintly orange hairs on its thorax .  Pale hairs cover most of its legs, and its knee-plates are pale orange.

ID:  Eucera paenalbata

Size:  10.5 mm  (female)

Associated plant:

Mexican hat

Rabatida columniferra

Cowpen daisy

Verbesina enceloides

Family: Asteraceae

When seen:  June 21 2021
Campos Viejos Ranch, 

Near Rio Grande City, Starr Co.

Female bee, Campos Viejos Ranch, Starr Co.
Female bee, Campos Viejos Ranch, Starr Co.

The bee's thorax hairs are faintly orange on top. Dense white hairs cover its face.

Face of bee. The bee's jaws are dark at the base and yellowish near the tips. The antennae are reddish-gold on the underside of the flagella above F2.

Alternate view of orange thorax hairs

Dorsal view

Close-up of vertex & thorax

female bee

female bee

Svastra atripes

Size:  16 mm (male)

Associated plant:

Cowpen daisy

Verbesina enceloides

Family: Asteraceae

When seen:  June 21, 2021
Campso Viejos Ranch,
Near Rio Grande City, Starr Co.

Male bee, Campo Viejo Ranch, Starr County
Male bee, Campo Viejo Ranch, Starr County

The hairs on the bee's lower as well as upper thorax are pale brown.

Lateral view of face, thorax & antennae

Alternate view

Dorsal view of thorax & vertex

male bee

Below are photos of the female Svastra atripes  dark morph that you identified last week from El Mesteno Ranch in NW Hidalgo Co.:

Female bee, Mesteno Ranch, NW Hidalgo Co.
Female bee, Mesteno Ranch, NW Hidalgo Co.

Alternate view of bee

Dorsal view of thorax

THE BEES BELOW HAVE BEEN IDENTIFIED ALREADY.

ID:  Svastra duplocincta

Size:  10 mm (female)

Associated plant:

Fishhook barrel cactus

Ferocactus wislizeni

Family:  Cactaceae

When seen:  June 18, 2021
Campo Viejo Ranch, Starr Co.

Female bee, Campo Viejo Ranch, Starr Co.
Female bee, Campo Viejo Ranch, Starr Co.

Face of bee

Dorsal view

Close-up of vertex & thorax

View of abdomen and hind legs

female bee

female bee

ID:  Agapostemon tyleri

Size:  10 mm (female)

Associated plants:

Cenizo 
Leucophyllum frutescens

Family:   Scrophulariaceae

Texas olive

Cordia boissieri

Family:   Acanthaceae

When seen:  June 17, 2021
Campo Viejo Ranch, Starr Co.

Female Bee, Campo Viejo Ranch, Starr County
Female Bee, Campo Viejo Ranch, Starr County

Dorsal view: the bee's wings are light brown.

The bee's face has a dark clypeal rim.

Additional view of face

The dominant  Agapostemon species at the Campo Viejo Ranch is  Agapostemon melliventris, but I found several male and females of the species shown here on cenizo and Texas olive.  Both the males (shown further down on page) and the females have black abdomens banded by white stripes.  The males' faces and legs fit the description of A. tyleri but not of A. leunculus or A. nusutus.

female bee

ID:  Agapostemon tyleri

Size: 10 mm (male)

Texas olive

Cordia boissieri

Family:   Acanthaceae

When seen:  June 17, 2021
Campo Viejo Ranch, Starr Co.

Male bee, Campo Viejo Ranch, Starr County
Male bee, Campo Viejo Ranch, Starr County

Face of male bee

Dorsal view

The inner hind femur and tibia of the male bee bear dark stripes that run the length of each segment. The hind femora are relatively slender.

male bee

ID:  Dianthidium discors

Size:  9 mm (female)

Associated plant:

Fishhook barrel cactus

Ferocactus wislizeni

Family:  Cactaceae

When seen:  June 18, 2021
Campo Viejo Ranch, Starr Co.

Female Bee, Campo Viejo Ranch, Starr Co.
Female Bee, Campo Viejo Ranch, Starr Co.

Lateral view of bee

Face

Dorsal view of abdomen & thorax

This bee likes to burrow into holes in barrel cactus.

female bee

female bee

Below are photos of a male Dianthidium discors that you identified on May 6:  this bee was from Starr County also. 

Male bee

ID:  Svastra sabinensis
Svastra (Epimelissodes) sabinensis

Family:  Apidae

Size:  11 mm  (male)

Floral Association:  

Cowpen daisy

(Verbesina encelioides) 

Plant Family:  Asteraceae

When seen:

June 18, 2021

Male bee, Campo viejo Ranch, Starr Co.
Male bee, Campo viejo Ranch, Starr Co.

Close-up of bee's face

Dorsal view of vertex & thorax

Antenna

This is a reddish-gold bee with vaguely-defined golden bands on its abdomen and two toothlike projections on S6.  It looked very different from the many Svastra petulca males in the area, which had much paler hairs and well-define broad bands of pale hair on their abdomens.

Male bee

Below are photos of a female Svastra sabinensis from Mission, identified by Karen Wright two years ago.

A female Sabine's Svastra