In Brazil, user @helio-lourencini has the only two iNat observations of Zethus miniatus with its communal nest, a most interesting behavior. It has been identified by @rblopes with the following explanation:

"This species seems to be common in Brazil, although I never got a glimpse of the nest in the wild; only in collections and pictures. It has been reported by Ducke in the early 1900s to have communal nesting (they build the nest together, but each female tends to their own offspring, there is no cooperative brood care). Closely related species like the Central American Z. olmecus may present a similar behavior, since their nests do look alike, but nothing has been officially published, as far as I know. Understanding the evolution of this type of nesting was part of a Post-doc project of mine, but lack of nests from other species complicated the study."

https://www.inaturalist.org/observations?verifiable=true&taxon_id=883640&place_id=&preferred_place_id=1&locale=en-US

Addendum: Rogério informs me that the nest is not made of mud, a I had assumed: “It is made of mastigated vegetable matter. In this case and in most other Zethines, the main building material is foliage.”

Thanks to some sleuthing from @ceiseman who has been going through many observations added to the project, and @harsiparker, the mysterious case of the mysterious case has been solved.

It had been observed by several users in North America and assumed to belong to Arthropoda, but it was, in fact, a geranium seed and its dispersal mechanism (a filament trailing from it).
Here it is:

https://www.inaturalist.org/observations/68020364

Staying with us is an observation from Ukraine (by @dinasafina) of Polistes dominula building a nest inside a chunk of animal bone:
https://www.inaturalist.org/observations/54959613

Happy observing!

Our first artist working with the medium of chocolate:

https://www.inaturalist.org/observations/66986297

A fly is suspected...

Happy chocolate season!

-The larva of a Keroplatidae species, Arachnocampa luminosa, is responsible for enchanting and deadly fairy light displays in the caves of Australia and New Zealand (media: silk and bioluminescence :)
Here they are:
https://www.inaturalist.org/observations?place_id=any&project_id=arthropod&subview=grid&taxon_id=125921&verifiable=any

-Meanwhile, in Chile, user @ieremiel has posted a GIF of a predatory fungus gnat larva at work, weaving:
https://www.inaturalist.org/observations/42130455

-Furthermore, one of my favorite ARThropod observation by @epopov has been identified (tentatively as these things are) as the pupa of Mycetophilidae (Fungus gnat):
https://www.inaturalist.org/observations/38438969

*Bonus: as I was looking into gnat larvae, I came across this macro photo blog by Andy Murray with amazing shots of the very festive and astonishing larvae of Forcipomyia, a member of Ceratopogonidae (Biting Midges ) and many other critters:
https://www.chaosofdelight.org/forcipomyia

Happy August and fruitful observing!

Some strange masses topped with little crowns have been causing some puzzlement and seem to be the work of Reduviidae.

Here are observations where the mass is quite jelly-like:
From Botswana: https://www.inaturalist.org/observations/44799788
From the USA (not identified): https://www.inaturalist.org/observations/47034015

And two where the eggs are more defined:
From the USA: https://www.inaturalist.org/observations/13772229
And: https://www.inaturalist.org/observations/47917091

The last one is actually my observation; these eggs are quite tiny and I did not discern the crown until I had my camera on them... I am looking everyday to see if they have hatched.
bugguide attributes the lastest or similar to Sinea:
https://bugguide.net/node/view/50716/bgpage

By the way, ARThropod has gone over a 1,000 observations of trippy, dreamy, creepy photographs and it's a wonderful collection!

-Biology student Mattia Menchetti gave wasps colored paper to make their nests:
https://www.mentalfloss.com/article/73212/rainbow-wasp-nest-was-built-colored-paper

-Artist Hubert Duprat gave caddisfly larvae gems and gold to make their cases:
https://www.thisiscolossal.com/2014/07/hubert-duprat-caddisflies/

These observations usually make me smile. Maybe they will make you smile too.

This interesting (mud???) case -make sure you click on photo 2 of the observation, for a game of peekaboo:
https://www.inaturalist.org/observations/39249029
Not identified by the way.

This industrious little larva, tunneling away. Let's see how fast you can spot it:
https://www.inaturalist.org/observations/13343384

The winner of all bagworm cases, daring engineering and somehow, a handle????
https://www.inaturalist.org/observations/32876491

Thanks @efarilis @carnifex and @rvp for your beautiful pictures.

Some interesting architecture:

The brutalist bunker of Pseudomasaris (a pollen wasp), in Canada:
https://www.inaturalist.org/observations/35871765

The concentric circle temple of Pheidole sykesii (an ant), in India:
https://www.inaturalist.org/observations/1857919

The undulating pipes of Trypoxylon politum (the Organ-pipe mud dauber wasp), in the US:
https://www.inaturalist.org/observations/32159890

This mysterious little tubular fort, hanging from a leaf, in Costa Rica; also a Mud-dauber?
https://www.inaturalist.org/observations/40020643

Spectacular glistening ring of eggs posted by @hannes_oehm. (look at pic 2; pic 1 is a side view)
An observation from Ghana.
Some Heteropteran?

https://www.inaturalist.org/observations/40189713

Welcome to ARThropod, unintentional art made by Arthropods and photographed by Humans.

So far, my top 4 artists and their photographers:

A wood bas-relief:
https://www.inaturalist.org/observations/38784785

A beaded leaf:
https://www.inaturalist.org/observations/38456671

A trichromatic mosaic:
https://www.inaturalist.org/observations/18178878

A silk and mixed media dreamcatcher:
https://www.inaturalist.org/observations/38438969