Editing Beetle (section)

===Head===
[[File:Head of the Weaver Beetle (Lamia textor).jpg|left|thumb|Front view of the head of ''[[Lamia textor]]'']]

The head, having mouthparts projecting forward or sometimes downturned, is usually heavily [[Sclerotin|sclerotized]] and is sometimes very large.<ref name="Gilliott"/> The eyes are [[compound eye|compound]] and may display remarkable adaptability, as in the case of the aquatic whirligig beetles ([[Gyrinidae]]), where they are split to allow a view both above and below the waterline. A few [[Longhorn beetle]]s ([[Cerambycidae]]) and weevils as well as some fireflies ([[Rhagophthalmidae]]) <ref name="Lau">{{ cite journal|author1=Lau T.F.S.| author2=Meyer-Rochow V.B.| title=Sexual dimorphism in the compound eye of ''Rhagophthalmus ohbai'' (Coleoptera; Rhagophthalmidae): I. Morphology and ultrastructure| date=2006| journal= Journal of Asia-Pacific Entomology| volume=9| pages=19–30| doi=10.1016/S1226-8615(08)60271-X}}</ref> have divided eyes, while many have eyes that are notched, and a few have [[ocelli]], small, simple [[eye]]s usually farther back on the head (on the [[Vertex (anatomy)|vertex]]); these are more common in larvae than in adults.<ref name='BeetlesAustralia'>{{cite book |author1=Hangay, G. |author2=Zborowski, P.|title=A Guide to the Beetles of Australia |url=https://archive.org/details/guidetobeetlesau00hang |url-access=limited |date=2010 |publisher=CSIRO |page=[https://archive.org/details/guidetobeetlesau00hang/page/n245 10]|isbn=978-0-643-09487-1}}</ref> The anatomical organization of the compound eyes may be modified and depends on whether a species is primarily crepuscular, or diurnally or nocturnally active.<ref name='beetles'>{{cite journal| author1= Gokan N.| author2= Meyer-Rochow V.B.|title=Morphological comparisons of compound eyes in Scarabaeoidea (Coleoptera) related to the beetles' daily activity maxima and phylogenetic positions| date=2000|journal=Journal of Agricultural Science (Tokyo Nogyo Daigaku)| volume=45| issue= 1|pages= 15–61}}</ref> Ocelli are found in the adult carpet beetle (as a single central ocellus in [[Dermestidae]]), some rove beetles ([[Omaliinae]]), and the [[Derodontidae]].<ref name='BeetlesAustralia'/>

[[File:Polyphylla fullo up.jpg|thumb|''[[Polyphylla fullo]]'' has distinctive fan-like [[antenna (biology)|antennae]], one of several distinct forms for the appendages among beetles.|left]]

Beetle [[antenna (biology)|antennae]] are primarily organs of sensory perception and can detect motion, odor and chemical substances,<ref name='Antennae'>{{cite web |url=http://www.kerbtier.de/Pages/Themenseiten/enKoerperbau.html#Fuehler |title=3. Antennae, Beetle morphology |last1=Benisch |first1=Christoph |date=2007 |publisher=Kerbtier.de (Beetle fauna of Germany) |access-date=2017-03-14}}</ref> but may also be used to physically feel a beetle's environment. Beetle families may use antennae in different ways. For example, when moving quickly, tiger beetles may not be able to see very well and instead hold their antennae rigidly in front of them in order to avoid obstacles.<ref>{{cite journal |doi=10.1098/rspb.2013.3072 |pmid=24500171 |title=Static antennae act as locomotory guides that compensate for visual motion blur in a diurnal, keen-eyed predator |journal=Proceedings of the Royal Society B: Biological Sciences |volume=281 |issue=1779 |page=20133072 |year=2014 |last1=Zurek |first1=D.B. |last2=Gilbert |first2=C. |pmc=3924084 }}</ref>
Certain Cerambycidae use antennae to balance, and blister beetles may use them for grasping. Some aquatic beetle species may use antennae for gathering air and passing it under the body whilst submerged. Equally, some families use antennae during mating, and a few species use them for defense. In the cerambycid ''[[Onychocerus albitarsis]]'', the antennae have venom injecting structures used in defense, which is unique among [[arthropod]]s.<ref>{{cite journal|doi=10.1007/s00114-007-0316-1|pmid=18004534|title=Convergent evolution in the antennae of a cerambycid beetle, ''Onychocerus albitarsis'', and the sting of a scorpion|journal=Naturwissenschaften|volume=95|issue=3|pages=257–61|year=2007|last1=Berkov|first1=Amy|last2=Rodríguez|first2=Nelson|last3=Centeno|first3=Pedro|bibcode=2008NW.....95..257B|s2cid=30226487}}</ref> Antennae vary greatly in form, sometimes between the sexes, but are often similar within any given family. Antennae may be [[wikt:clavate|clubbed]], [[wikt:filiform|threadlike]], [[wikt:geniculate|angled]], [[wikt:moniliform|shaped like a string of beads]], [[wikt:pectinate|comb-like]] (either on one side or both, bipectinate), or [[wikt:serrate|toothed]]. The physical variation of antennae is important for the identification of many beetle groups. The Curculionidae have elbowed or geniculate antennae. Feather like flabellate antennae are a restricted form found in the Rhipiceridae and a few other families. The Silphidae have a capitate antennae with a spherical head at the tip. The Scarabaeidae typically have lamellate antennae with the terminal segments extended into long flat structures stacked together. The Carabidae typically have thread-like antennae. The antennae arises between the eye and the mandibles and in the Tenebrionidae, the antennae rise in front of a notch that breaks the usually circular outline of the compound eye. They are segmented and usually consist of 11 parts, the first part is called the scape and the second part is the pedicel. The other segments are jointly called the flagellum.<ref name='Antennae'/><ref>{{cite web |url=http://bugs.bio.usyd.edu.au/learning/resources/Entomology/externalMorphology/antennaTypes.html |title=Antennae Types |publisher=University of Sydney |access-date=2017-01-26 |archive-date=February 22, 2018 |archive-url=https://web.archive.org/web/20180222221339/http://bugs.bio.usyd.edu.au/learning/resources/Entomology/externalMorphology/antennaTypes.html  }}</ref><ref>{{cite book |title=American Beetles, Volume I: Archostemata, Myxophaga, Adephaga, Polyphaga: Staphyliniformia |author1= Arnett, R. H. Jr.|author2=Thomas, M. C. |date=2001 |publisher=CRC Press |isbn=978-1-4822-7432-5 |pages=3–7}}</ref>

Beetles have [[Insect mouthparts|mouthparts]] like those of [[grasshopper]]s. The [[mandible (insect)|mandibles]] appear as large pincers on the front of some beetles. The mandibles are a pair of hard, often tooth-like structures that move horizontally to grasp, crush, or cut food or enemies (see [[#Anti-predator adaptations|defence]], below). Two pairs of finger-like appendages, the maxillary and labial palpi, are found around the mouth in most beetles, serving to move food into the mouth. In many species, the mandibles are sexually dimorphic, with those of the males enlarged enormously compared with those of females of the same species.<ref name="Gilliott"/>