What is Apterygota?
{{Taxobox | name = Apterygota | fossil_range = {{Fossil range|Devonian|Recent}}<ref name=IIBD1>{{cite book |author= Hoell, H.V., Doyen, J.T. & Purcell, A.H. |year=1998 |title=Introduction to Insect Biology and Diversity, 2nd ed. |url= https://archive.org/details/introductiontoin0000daly |publisher= Oxford University Press |page= [https://archive.org/details/introductiontoin0000daly/page/320 320]|isbn= 0-19-510033-6}}</ref> | image = Archaeognatha.jpg | image_caption = ''Petrobius maritimus''<br />([[Archaeognatha]]: Machilidae) | regnum = [[Animal]]ia | phylum = [[Arthropod]]a | classis = [[Insect]]a | subclassis = '''Apterygota'''[[Paraphyletic|†]] | subdivision_ranks = Orders | subdivision = *[[Archaeognatha]] *[[Thysanura]] *Monura ''(extinct)'' }} The '''Apterygota''' are a small [[Subclass (biology)|subclass]] of primitive [[insect]]s. They are insects which have never had [[wing]]s at any time in their [[evolution]]ary history. Their first known occurrence in the fossil record is in the [[Rhynie chert]] of the [[Devonian]] period, ~400 million years ago. While some other insects, such as [[flea]]s, also lack wings, these are descended from winged insects, and have lost them during the course of evolution. By contrast, the apterygotes are a primitive group of insects that diverged from other orders before wings evolved. They have some other primitive [[trait]]s (features). The [[nymph (biology)|nymphs]] (younger stages) go through little or no [[metamorphosis]], so they look like the adults. They continue to [[moult]] throughout life, with multiple [[instar]]s (stages) after reaching sexual maturity. All other insects have only a single sexually mature adult stage. Their skin is thin, making them appear translucent. Males deposit [[sperm]] packages rather than fertilising the female internally.<ref name=IIBD>{{cite book |author= Hoell, H.V., Doyen J.T. & Purcell A.H. |year=1998 |title=Introduction to insect biology and diversity |url= https://archive.org/details/introductiontoin0000daly |publisher= 2nd