North America: 1 native species, 5 introduced species.
Up to 16mm in length, 0.9 mm in diameter. (1)
Cylindrical body, relatively long and thin, with a length:width ratio of up to 30:1. Members have distinctive spots on each segments: the odiferous glands. Eyes may be present or absent (eyeless species pale in color). If present, eyes are in one or two simple rows, rather than a large ocular field. First pair of legs in mature males is short, hook-like. Compared to members of Julidae and Parajulidae, no species possess a posterior projection of the pre-anal ring. (1)
Predominantly Palearctic: species from Western Europe have been widely introduced in Eastern North America.(2)
. Some species in the West. See Remarks below.
The only native species known is the U.S. endemic Virgoiulus minutus
, known from Pennsylvania and Missouri south to Florida and Louisiana.(2)
Archiboreoiulus pallidus - Eastern U.S. and Canada to North Dakota
Blaniulus guttulatus - Widespread: "ubiquitous" in North America
Proteroiulus fuscus - Eastern North America
Choneiulus palmatus - Widespread: from Nova Scotia to Washington and California, unknown south of Pennsylvania
Nopoiulus kochii - Nova Scotia to Virginia, Washington State