Bombylius major

 I didn't know what this Bee-fly was doing so I consulted Gemini AI....

"It looks like you’ve captured a Dark-edged Bee-fly (Bombylius major) in a very specific, fascinating moment of its life cycle.

While they might look like fuzzy little bees, they are actually a highly specialised type of fly. Based on the video, here is what is likely happening:

The "Tail-Dipping" Ritual

What you are seeing on that patch of dry earth isn't just resting; it is likely a female bee-fly preparing for motherhood.

• Collecting Dust: Female bee-flies have a specialised chamber at the end of their abdomen. They hover or crawl over dry, loose soil and "dip" their tails into it to collect fine dust or sand.

• Arming the Eggs: She uses this dust to coat her eggs. This makes the eggs heavier (for better "bombing" accuracy) and provides a level of camouflage or protection from the elements.

• The Bombing Run: Once her eggs are coated, she will fly over the entrance holes of solitary bees (like mining bees). She flickers her abdomen mid-air to "fire" an egg into or near the bee's nest.

Why do they do this?

Bee-flies are parasitoids. Once the bee-fly egg hatches near a solitary bee's nest, the larva crawls inside and waits for the bee larva to grow. Eventually, the bee-fly larva consumes the bee larva before pupating and emerging the following spring.

Key Features in your Video

• The Proboscis: You can clearly see that long, needle-like "nose." It’s actually harmless to humans and is used solely for drinking nectar from flowers.

• Hovering Ability: Note how it moves with the precision of a miniature helicopter—this agility is what allows them to be so accurate during their egg-laying "bombing runs."

It's a great find! These are one of the surest signs of spring in a garden or along a sunny path"

It went on to say this

"It’s quite a tactical operation for such a small insect. The process is so specialised that entomologists often refer to that specific part of her anatomy as a "sand chamber" or "dust basket."

While she looks like she's just basking on the ground, she is actually "loading up." Here’s why that dust coating is a mechanical necessity for her:

The Engineering of the "Bomb"

• Ballistics: An uncoated bee-fly egg is incredibly light and translucent. By dabbing her abdomen into the dry earth, she mixes the eggs with fine grit. This adds just enough mass to ensure that when she "flicks" her abdomen, the egg has the momentum to reach the dark shadows of a mining bee's burrow rather than just drifting away in a breeze.

• Desiccation Protection: The dust acts as a physical barrier, helping to prevent the egg from drying out in the sun before it hatches.

• Camouflage: Coating the egg in local soil makes it nearly invisible to other predators or even the host bee, should she return to the nest entrance.

The "Planidium" Stage

Once that dusty egg hatches, a tiny larva emerges called a planidium. Unlike the fat, legless maggots we usually associate with flies, these are highly active and have bristles to help them "trek" through the soil and into the depths of the bee's nest. They are essentially the ground-force units that complete the mission after the mother has finished her aerial bombardment.

It's a brilliant bit of natural engineering—turning a bit of garden dirt into a precision-guided coating.

Did you happen to see any small, volcano-like mounds of soil nearby? Those would be the mining bee burrows she was likely targeting."
There aren't any mounds of soil in the garden, So the mining bees must have a nest in the vicinity