Passandridae

Histeridae is a family of beetles commonly known as clown beetles or hister beetles. This very diverse group of beetles contains 3,900 species found worldwide. They can be easily identified by their shortened elytra that leaves two of the seven tergites exposed, and their geniculate (elbowed) antennae with clubbed ends. These predatory feeders are most active at night and will fake death if they feel threatened. This family of beetles will occupy almost any kind of niche throughout the world. Hister beetles have proved useful during forensic investigations to help in time of death estimation. Also, certain species are used in the control of livestock pests that infest dung and to control houseflies. Because they are predacious and will even eat other hister beetles, they must be isolated when collected.

The Cucujidae, "flat bark beetles," are a family of distinctively flat beetles found worldwide under the bark of dead trees. The family has received considerable taxonomic attention in recent years and now consists of 70 species distributed in five genera. It was indicated Cucujus species are scavengers, only feeding on pupae and larvae of other insects and on other subcortical beetles such as their own. Since the Cucujidae prey on larvae of potentially tree damaging beetles that spread fungal diseases, they are considered to be beneficial to the health of living trees.

Myxophaga is the second-smallest suborder of the Coleoptera after Archostemata, consisting of roughly 65 species of small to minute beetles in four families. The members of this suborder are aquatic and semiaquatic, and feed on algae.

Cucujoidea is a superfamily of beetles. This group formerly included all of the families now included in the superfamily Coccinelloidea. They include some fungus beetles and a diversity of lineages of "bark beetles" unrelated to the "true" bark beetles (Scolytinae), which are weevils.

The Lymexylidae, also known as ship-timber beetles, are a family of wood-boring beetles. Lymexylidae belong to the suborder Polyphaga and are the sole member of the superfamily Lymexyloidea.

Zopheridae is a family of beetles belonging to Tenebrionoidea. It has grown considerably in recent years as the members of two other families have been included within its circumscription; these former families are the Monommatidae and the Colydiidae, which are now both included in the Zopheridae as subfamilies or even as tribe of subfamily Zopherinae. Some authors accept up to six subfamilies here, while others merge all except the Colydiinae into the Zopherinae.

Colydiinae is a subfamily of beetles, commonly known as cylindrical bark beetles. They have been treated historically as a family Colydiidae, but have been moved into the Zopheridae, where they constitute the bulk of the diversity of the newly expanded family, with about 140 genera worldwide. They are diverse for example in the Australian region, from where about 35 genera are known; in Europe, though, only 20 genera are found and many of these only with few species.

Ptiliidae is a family of very tiny beetles with a cosmopolitan distribution. They are colloquially called featherwing beetles, because the hindwings are narrow and feathery.

Jacobsoniidae are a family of tiny beetles belonging to Staphylinoidea. The larvae and adults live under bark, in plant litter, fungi, bat guano and rotten wood. There are around 28 described species in three genera:

Prionoceridae is a small family of beetles, in the suborder Polyphaga. They form a group within the cleroid beetles and were formerly treated as a subfamily (Prionocerinae) within the family Melyridae. Very little is known of their life history but most species are pollen feeders as adults and occur in large numbers during spring or the host flowering season. Larvae are predatory or feed on decomposing wood.

Trogossitidae, also known as bark-gnawing beetles, are a small family in the superfamily Cleroidea. Many taxa formerly within this family have been removed to other families, such as Lophocateridae, Peltidae, Protopeltidae, Rentoniidae, and Thymalidae. Members of the family are generally predatory and/or feed on fungi, both in adult and larval stages, and are generally associated with wood, being found under bark or inside bored tunnel galleries. There are about 400 species in 25 genera in the family under the new, restricted circumscription, as opposed to 600 species in over 50 genera in the old definition. The oldest fossil assignable to the modern, more restricted definition of the family is Microtrogossita from the mid-Cretaceous Burmese amber of Myanmar, which has close affinities to the Trogossitini, indicating that the family had already considerably diversified by this time.

Bothrideridae is a family of beetles in the superfamily Coccinelloidea. They are known commonly as the cocoon-forming beetles or dry bark beetles. They occur worldwide with most native to the Old World tropics. In older literature, the family was often included in the family Colydiidae, but is now considered unrelated.

Laemophloeidae, "lined flat bark beetles," is a family in the superfamily Cucujoidea characterized by predominantly dorso-ventrally compressed bodies, head and pronotal discs bordered by ridges or grooves, and inverted male genitalia. Size range of adults is 1–5 mm (0.04–0.2 in) in length. Currently, it contains 40 genera and about 450 species, and is represented on all continents except Antarctica; species richness is greatest in the tropics.

Silvanidae, "silvan flat bark beetles", is a family of beetles in the superfamily Cucujoidea, consisting of 68 described genera and about 500 described species. The family is represented on all continents except Antarctica, and is most diverse at both the generic and species levels in the Old World tropics.

Phloeostichidae is a family of beetles in the superfamily Cucujoidea. They are typically found under the bark of dead trees. Larvae have been found to consume plant tissue and some fungi, while the adults appear to be exclusively fungivores. The family contains four extant genera, Phloeostichus is native to the Palearctic, Rhopalobrachium is native to central-southern South America and eastern Australia, Hymaea is native to southeastern Australia, and Bunyastichus is found in Tasmania.

Monotomidae is a family of beetles in the superfamily Cucujoidea. The family is found worldwide, with approximately 240 species in 33 genera. The ecological habits of the family are diverse, with different members of the group being found under tree bark, in decaying vegetation, on flowers and in ant nests. Their ecology is obscure, while at least some species are mycophagous, feeding on the fruiting bodies of ascomycete fungi, Rhyzophagus are predators on bark beetles and possibly Phoridae larvae, with the larvae of some species also being mycophagous.

Teredidae is a family of beetles in the superfamily Coccinelloidea, formerly included within the family Bothrideridae. There are around 160 species in 10 genera, found worldwide except South America. Teredids are generally found under bark, in the galleries of wood-boring beetles, or in leaf litter. They are thought to be fungivores. The oldest records of the family are Delteredolaemus from mid-Cretaceous aged Burmese amber from Myanmar and a species of Teredolaemus from Eocene aged Baltic amber.

Artematopodidae is a family of soft-bodied plant beetles in the superfamily Elateroidea. They are mostly found in understory forest foliage. The life history of the group is obscure, larvae of the genera Eurypogon and Macropogon likely feed on moss, while the larvae of Artematopus have been fed insect remains. The oldest fossils of the family date to the Middle Jurassic.