Monommatinae is a subfamily (or sometimes only considered a tribe) of beetle

Beetle

Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...

s with no vernacular common name, though recent authors have coined the name opossum beetles. They have been treated historically as a family (sometimes spelled Monommidae), but have recently been placed into the Zopheridae

Zopheridae

Zopheridae is a family of beetles that 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 considered subfamilies within the Zopheridae. There are...

. There are some 15 genera in this group, commonly found in association with plants in the family Agavaceae

Agavaceae

Agavoideae is a subfamily of monocot flowering plants in the family Asparagaceae, order Asparagales. It has previously been treated as a separate family, Agavaceae. The group includes many well-known desert and dry zone types such as the agave, yucca, and Joshua tree...

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