Editing Caterpillar (section)

== Description ==
[[File:Pfurtscheller_Table_23.png|thumb|Anatomy - (1) Egg m-micropyle (2) Head o-ocelli s-spiracle (3) s-spiracle m-malphigian tubules g-silk gland  (4) a - antenna l-labrum o- ocelli k mandible k2 maxilla t2 palps t3 spinnerets]]
[[File:Crochets.jpg|thumb|upright|Crochets on a caterpillar's prolegs]]
[[File:Craesus septentrionalis.jpg|thumb|Larvae of ''[[Craesus septentrionalis]]'', a [[sawfly]] showing six pairs of prolegs.]]

Caterpillars have soft bodies that can grow rapidly between moults. Their size varies between species and [[instar]]s (moults) from as small as {{Convert|1|mm|in}} up to {{Convert|14|cm|in}}.<ref>{{cite web|url=http://entnemdept.ufl.edu/creatures/bfly/regal_moth.htm|title=Featured Creatures: hickory horned devil, ''Citheronia regalis''|last=Hall|first=Donald W.|date=September 2014|website=University of Florida, Entomology and Nematology Department|access-date=19 September 2017|archive-date=1 October 2017|archive-url=https://web.archive.org/web/20171001234738/http://entnemdept.ufl.edu/creatures/bfly/regal_moth.htm|url-status=live}}</ref> Some larvae of the order [[Hymenoptera]] (ants, bees, and wasps) can appear like the caterpillars of the Lepidoptera. Such larvae are mainly seen in the [[sawfly]] suborder. However while these larvae superficially resemble caterpillars, they can be distinguished by the presence of [[proleg]]s on every abdominal segment, an absence of crochets or hooks on the prolegs (these are present on lepidopteran caterpillars), one pair of prominent [[ocelli]] on the head capsule, and an absence of the upside-down Y-shaped [[suture (anatomical)|suture]] on the front of the head.<ref name="scoble">Scoble, MJ. 1995. [https://books.google.com/books?id=gnpd_5iNTiwC ''The Lepidoptera: Form, Function and Diversity''] {{Webarchive|url=https://web.archive.org/web/20131231191542/http://books.google.com/books?id=gnpd_5iNTiwC&printsec=frontcover |date=2013-12-31 }}. Oxford Univ. Press. {{ISBN|0-19-854952-0}}</ref>

Lepidopteran caterpillars can be differentiated from sawfly larvae by:
* the numbers of pairs of pro-legs; sawfly larvae have 6 or more pairs while caterpillars have a maximum of 5 pairs.
* the number of [[stemmata]] (simple eyes); the sawfly larvae have only two,<ref name="Meyer-Rochow 1974">{{cite journal |last=Meyer-Rochow |first=Victor Benno |title=Structure and function of the larval eye of the sawfly Perga |journal=[[Journal of Insect Physiology]] |year=1974 |volume=20 |issue=8 |pages=1565–1591 |doi=10.1016/0022-1910(74)90087-0 |pmid=4854430|bibcode=1974JInsP..20.1565M }}</ref> while caterpillars usually have twelve (six each side of the head).
* the presence of crochets on the prolegs; these are absent in the sawflies.
* sawfly larvae have an invariably smooth head capsule with no cleavage lines, while lepidopterous caterpillars bear an inverted "Y" or "V" (frontal suture).

=== Fossils ===
[[File:Eogeometer valdens holotype 01.jpg|thumb|''[[Eogeometer vadens]]'', the earliest known [[geometrid moth]] caterpillar found in [[Baltic amber]]<ref name="Fischer_al.2019" /><ref name="DW 11-2019" /><ref name="Newsweek 11-2019" />]]

[[2019 in insect paleontology#Other insects|In 2019]], a [[geometrid moth]] caterpillar dating back to the [[Eocene]] [[Epoch (geology)|epoch]], approximately 44 [[Mya (unit)|million years ago]], was found preserved in [[Baltic amber]]. It was described under ''[[Eogeometer vadens]]''.<ref name="Fischer_al.2019">{{cite journal |last1=Fischer |first1=Thilo C. |last2=Michalski |first2=Artur |last3=Hausmann |first3=Axel |year=2019 |title=Geometrid caterpillar in Eocene Baltic amber (Lepidoptera, Geometridae) |journal=[[Scientific Reports]] |volume=9 |issue=1 |pages=Article number 17201 |doi=10.1038/s41598-019-53734-w |pmid=31748672 |pmc=6868187 |bibcode=2019NatSR...917201F}}</ref><ref name="DW 11-2019">{{cite news |last=Muller |first=Natalie |title=German scientists find 44-million-year-old caterpillar |newspaper=[[DW News|DW]] |url=https://www.dw.com/en/german-scientists-find-44-million-year-old-caterpillar/a-51341040 |date=20 November 2019 |access-date=23 November 2019 |archive-date=21 November 2019 |archive-url=https://web.archive.org/web/20191121214607/https://www.dw.com/en/german-scientists-find-44-million-year-old-caterpillar/a-51341040 |url-status=live }}</ref><ref name="Newsweek 11-2019">{{cite news |last=Georgiou |first=Aristos |title=Scientists discover 'exceptional' 44-million-year-old caterpillar preserved in amber |newspaper=[[Newsweek]] |url=https://www.newsweek.com/scientists-exceptional-caterpillar-preserved-amber-1473293 |date=21 November 2019 |access-date=24 November 2019 |archive-date=23 November 2019 |archive-url=https://web.archive.org/web/20191123221345/https://www.newsweek.com/scientists-exceptional-caterpillar-preserved-amber-1473293 |url-status=live }}</ref> Previously, another fossil dating back approximately 125 million years was found in [[Lebanon|Lebanese]] [[amber]].<ref name="GrimaldiEngel2005">{{cite book |last1=Grimaldi |first1=David |author-link1=David Grimaldi (entomologist) |last2=Engel |first2=Michael S. |author-link2=Michael S. Engel |date=June 2005 |title=Evolution of the Insects |publisher=[[Cambridge University Press]] |isbn=978-0-5218-2149-0 |url=https://www.cambridge.org/gb/academic/subjects/life-sciences/entomology/evolution-insects?format=HB&isbn=9780521821490#ZEGmsTMLBuLrPUhV.97 |access-date=2019-11-24 |archive-date=2018-10-19 |archive-url=https://web.archive.org/web/20181019035838/https://www.cambridge.org/gb/academic/subjects/life-sciences/entomology/evolution-insects?format=HB&isbn=9780521821490#ZEGmsTMLBuLrPUhV.97 |url-status=live }}</ref><ref name="TheConversation 01-2018">{{cite web |last=Martill |first=David |title=Scientists have accidentally found the oldest ever butterfly or moth fossils |website=[[The Conversation (website)|The Conversation]] |url=https://theconversation.com/scientists-have-accidentally-found-the-oldest-ever-butterfly-or-moth-fossils-90029 |date=13 January 2018 |access-date=24 November 2019 |archive-date=28 November 2019 |archive-url=https://web.archive.org/web/20191128191146/http://theconversation.com/scientists-have-accidentally-found-the-oldest-ever-butterfly-or-moth-fossils-90029 |url-status=live }}</ref>