Identification, Images, & Information
For Insects, Spiders & Their Kin
For the United States & Canada
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Order Strepsiptera - Twisted-winged Insects

 Stylopized Sphecid - Paraxenos Strepsiptera - Halictophagus - female Wasp parasite - Xenos Northern Paper Wasp with Strepsipterans? - Xenos - female Mystery pool bug another bee - Stylops another bee - Stylops Doin the Dirty - Halictoxenos - male
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Strepsiptera (Twisted-winged Insects)
Synonyms and other taxonomic changes
group that is sister to beetles(1) and used to be included in beetles by some workers(2)
Explanation of Names
Greek streptos (στρεψισ) 'twisted' + pteron (πτερον) 'wing'(3)
84 spp. in 11 genera of 5 families in our area(4); worldwide, ~600 spp. in 43 genera of 10 families(5) arranged in 2 suborders, Mengenillidia (a single family, Mengenillidae of a dozen spp.) and Stylopidia (7 families)(6)(7)
Overview of our fauna (* –taxa not yet in the guide; classification per(5))
Order Strepsiptera
Family Corioxenidae
Family *Elenchidae
Family Stylopidae
0.5-4 mm(8)
Adult females are larviform/neotenic endoparasites; adult males are free-living, and their sole mission is to find and fertilize a female. They have reduced forewings and fan-shaped hind wings, branched antennae, and raspberry-like eyes, unique among living insects and somewhat similar to the eyes of trilobites.(7)
Key to families (adult males) in(4)
worldwide; suborder Stylopidia is cosmopolitan (2 families of 2 spp. each are restricted to the Neotropical and Oriental regions, respectively), Mengenillidia is an Old World group(7), the recently discovered monotypic Bahiaxenidae is a "living fossil" from Brazil(5)
obligate parasites of insects (hosts include members of 7 orders and 34 families)(7)
Life Cycle
Apart from the adult males, the only free-living stages are the viviparous 1st instar host-seeking larvae(7); the larvae hatch as free agents from eggs laid on flowers. When a suitable host visits the flower, the first stage larvae attach themselves to it and become parasitic.(8)
Internet References
Fact sheets from Virginia Tech(9) and Discover Life