Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada

Genus Rhyzobius

Tiny beetle - Rhyzobius lophanthae Diomus species? - Rhyzobius lophanthae Scymnus? - Rhyzobius forestieri Lady Beetle - Rhyzobius lophanthae Rhizobius lophanthae? - Rhyzobius lophanthae Scymnus (?) with dark legs and orange-red posterior venter - Rhyzobius Scymnus? - Rhyzobius lophanthae Rhyzobius lophanthae
Classification
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Polyphaga
No Taxon (Series Cucujiformia)
Superfamily Coccinelloidea
No Taxon (Coccinellid group)
Family Coccinellidae (Lady Beetles)
Subfamily Coccidulinae
Tribe Coccidulini
Genus Rhyzobius
Synonyms and other taxonomic changes
First described in 1832 by James Francis Stephens as Rhyzobius. The correct spelling according to the Greek should be Rhizobius, but the rules don't allow a correction in this case. As a result, both spellings are widespread.
Explanation of Names
from Greek rhiza (ριζα)- "root" + bios (βιος)- "life, way of life". The species best known at the time lives at the roots of plants.
Numbers
Two introduced species in North America:
Size
1.5-3.7 mm long
Identification
Dark reddish-brown or black
Metallic
Densely pubescent (hairy), with a layer of short fine hairs interspersed with some longer hairs; densely "fuzzy" appearance.
Eyes not pubescent
Range
Rhyzobius forestieri: Western California.
Rhyzobius lophanthae: Transcontinental in the southern U.S.
Food
Scale insects.
See Also
Dusky Lady Beetles of Tribe Scymnini look extremely similar, with dark brown or black coloration and pubescence. However, all members of Tribe Scymnini have pubescent eyes and none are metallic. They also have hairs of a single length, not two layers of longer and shorter hairs like Rhyzobius.
Internet References
Illustrations of British Entomology, p.396    Stephens' original description of the genus.