A leaf cutter bee of the genus Megachile. There are likely 15 to 20 species in Arkansas in this genus. Some in this group are mason bees and some are leaf cutters. All use nectar and pollen for storage supplies for their offspring. The pollen is carried in a special sac under the abdomen instead of on the legs as in many bees. It is difficult to see in this shot.

High pitched buzz, you can often find them by listening for this sound above the other honeybee and bumble drones. These guys proceed from flower to flower and dive deep inside. They usually flip over to expose that pollen yellow underside in this maneuver.

This is almost certainly the insect mimicked by the Megaphorus robber flies (see that page). There are five or six other likely genera in the Megachilidae in Arkansas. List in progress.

Very wide set eyes. You can see the underside of the abdomen better here. They rarely stop in their busy goings to rest. This one did.

This appears to be another leafcutter and a handsome one nectaring on the Verbena in the yard. This did not have an intense buzz to its flight.

And the Apidae is a large group that I have not focused on. Though I have watched them. I believe this April animal is a member and likely in the genus Anthophora. They are Digger bees, pollen collectors. All dig in soil and make cellular partitions for the next generation. It is a large group worldwide just for this genus.