Primitive-insect
Guides
Allacrotelsa
Allacrotelsa is a genus of primitive wingless insects in the family Lepismatidae, order Zygentoma. These insects are commonly known as silverfish or bristletails. The genus was established by Silvestri in 1935. Species in this genus share characteristics with other Lepismatidae, including elongated bodies and three tail-like appendages at the abdomen tip.
Ctenolepisma
Ctenolepisma is a genus of primitive wingless insects in the order Zygentoma, family Lepismatidae. The genus comprises approximately 75 extant species distributed nearly worldwide in warm regions, with some species occurring both indoors and outdoors while others are found exclusively in natural habitats. Unlike the closely related silverfish (Lepisma saccharina) and firebrat (Thermobia domestica), many Ctenolepisma species are less dependent on human habitation. Australia lacks native species but hosts introduced populations. The genus has undergone taxonomic revision, with ICZN Opinion 2427 (2018) establishing the neuter gender of Lepisma and related genera, resulting in species epithet changes such as Ctenolepisma longicaudatum (formerly longicaudata).
Hypomachilodes texanus
Hypomachilodes texanus is a species of bristletail in the family Meinertellidae, first described by Silvestri in 1911. It belongs to the order Archaeognatha (also known as Microcoryphia), an ancient group of wingless insects with a fossil record extending back to the Devonian period. The species is known from North America, with records indicating presence in the region. Like other bristletails, it is a primitive hexapod with distinctive morphological features including large compound eyes that meet dorsally and the ability to spring-jump using its caudal appendages.
Lepisma saccharinum
Common Silverfish, Silverfish
Lepisma saccharinum, commonly known as the silverfish, is a small, wingless insect in the order Zygentoma. It derives its common name from its silvery coloration and fish-like undulating movements. This species is cosmopolitan in distribution and frequently found in human dwellings, where it feeds on starchy materials.
Machilinae
Machilinae is a subfamily of bristletails within the family Machilidae, comprising one of the two major lineages of the jumping bristletail family. Members are small, wingless insects with the characteristic arched thorax and springing organ (furcula) that enables their distinctive jumping locomotion. The subfamily has been historically distinguished from the other machilid subfamily, Petrobiinae, primarily by subtle differences in abdominal appendage structure and scale patterns. Machilinae species are found across temperate and Mediterranean regions, often occupying rocky, coastal, or urban habitats.
Machiloides banksi
rock bristletail
Machiloides banksi is a species of rock bristletail described by Filippo Silvestri in 1911. It belongs to the family Meinertellidae, a group of basal insects in the order Archaeognatha. The species is known from the eastern United States. Like other Archaeognatha, it represents one of the most primitive lineages of living insects, retaining ancestral characteristics such as the ability to spring using its caudal filaments.
Microcoryphia
bristletails
Microcoryphia is an order of wingless hexapods commonly known as bristletails, representing one of the two extant orders of apterygote insects. They retain numerous ancestral characteristics that make them significant for understanding early insect evolution, including monocondylic mandibles and the ability to molt throughout their entire life. The group is distinguished by their laterally compressed bodies, large compound eyes, and three long caudal filaments. Approximately 500 species have been described worldwide, with new species continuing to be discovered in diverse habitats including leaf litter, rocky areas, and caves.
Neohermes californicus
California fishfly
Neohermes californicus is a species of fishfly in the family Corydalidae, first described by Walker in 1853 as Chauliodes californicus. It belongs to the order Megaloptera, a small group of primitive holometabolous insects that includes fishflies, dobsonflies, and alderflies. The species is found in North America, particularly in western regions including California. Fishflies in this genus are associated with aquatic habitats during their larval stages. Adults are typically nocturnal and attracted to lights.
Nicoletiidae
Nicoletiidae is a family of primitive wingless insects in the order Zygentoma. Members are predominantly subterranean, inhabiting soil, caves, and mesovoid shallow substratum (MSS) environments. Many species exhibit troglobiotic adaptations including lack of eyes and pigmentation. The family contains at least four subfamilies (Atelurinae, Nicoletiinae, Cubacubaninae, Coletiniinae, Subnicoletiinae) with over 100 described genera. Some species are commensals in social insect nests, such as Allotrichotriura saevissima in fire ant nests.
Pedetontus saltator
jumping bristletail
Pedetontus saltator is a species of jumping bristletail, a primitive wingless insect in the family Machilidae. It is found in North America, including records from Vermont in the United States. As a member of Archaeognatha, it represents one of the most basal lineages of living insects, retaining characteristics of early insect evolution.
Petridiobius arcticus
Arctic Bristletail
Petridiobius arcticus is a species of jumping bristletail, an ancient lineage of wingless insects belonging to the order Archaeognatha. As a member of the family Machilidae, it represents one of the most primitive insect groups, retaining characteristics of early insect evolution. The species has a broad distribution spanning multiple continents, occurring in both the Palearctic and Nearctic regions. Despite its wide geographic range, detailed biological information remains limited.
Thermobia domestica
Firebrat
Thermobia domestica, commonly known as the firebrat, is a small hexapod in the order Zygentoma, closely related to silverfish. It is distinguished by its preference for hot environments, particularly steam-heated buildings and boiler rooms. The species exhibits pheromone-mediated aggregation behavior requiring physical contact for recognition. It feeds on carbohydrates, especially starchy materials, and can be a minor pest in libraries and storage facilities.
Trigoniophthalmus
Trigoniophthalmus is a genus of jumping bristletails in the family Machilidae, order Archaeognatha. The genus was erected by Verhoeff in 1910 and contains approximately 11-14 described species distributed across the Palaearctic region. Taxonomic revision in 2019 established two subgenera: Trigoniophthalmus s. str. and Silvestrius subgen. nov. Species within this genus are distinguished by morphological features of the compound eyes, ocelli, and ovipositor structure.
Trigoniophthalmus alternatus
Cave Bristletail
Trigoniophthalmus alternatus is a species of jumping bristletail, a primitive wingless insect in the order Archaeognatha. It is commonly known as the Cave Bristletail due to its association with subterranean and dark, moist habitats. The species has a broad distribution across Europe, Northern Asia (excluding China), and North America. It was originally described as Machilis alternatus by Silvestri in 1904 before being transferred to the genus Trigoniophthalmus.