12 cm stick insect! Taken at night in Singapore.
Quote from en.wikipedia.org/wiki/Phasmato…
The Phasmatodea (sometimes called Phasmida or Phasmatoptera) are an order of insects, whose members are variously known as stick insects (in Europe and Australasia), walking sticks or stick-bugs (in the United States and Canada), phasmids, ghost insects and leaf insects (generally the family Phylliidae). The ordinal name is derived from the Ancient Greek φάσμα phasma, meaning an apparition or phantom, and refers to the resemblance of many species to sticks or leaves. Their natural camouflage can make them extremely difficult to spot. Phasmatodea can be found all over the world in warmer zones, especially the tropics and subtropics. The greatest diversity is found in Southeast Asia and South America, followed by Australia. Phasmids also have a considerable presence in the continental United States, mainly in the Southeast.
Phasmids can be relatively large, ranging from 2.5 centimetres (0.98 in) to over 30 centimetres (12 in) in length. Females of the genus Phobaeticus are the world's longest insects, measuring up to 56.7 centimetres (22.3 in) in total length in the case of Phobaeticus chani, including the outstretched legs. Females of the species Heteropteryx dilatata are the heaviest known phasmids, possibly weighing in excess of 65 grams.
Some have cylindrical stick-like bodies, while others have flattened, leaflike shapes. The thorax is long in the winged species, since it houses the flight muscles, but is typically much shorter in the wingless forms. Where present, the first pair of wings is narrow and cornified, while the hind wings are broad, with straight longitudinal veins and multiple cross-veins. The body is often further modified to resemble vegetation, with ridges resembling leaf veins, bark-like tubercles, and other forms of camouflage. A few species, such as Carausius morosus, are even able to change their pigmentation to match their surroundings. Many species are wingless, or have reduced wings. The mouthparts project out from the head. Chewing mandibles are uniform across species. The legs are typically long and slender, and some species are capable of limb autotomy. They have long, slender antennae, as long or longer than the length of the body in some species.
All phasmids possess compound eyes, but ocelli are only found in some winged males. Phasmids have an impressive visual system that allow them to perceive significant detail even in dim conditions, which suits their typically nocturnal lifestyle. They are born equipped with tiny compound eyes with a limited number of facets. As the insect grows through successive molts, the number of facets is increased along with the number of photoreceptor cells in the eye. The sensitivity of the adult eye is at least tenfold that of the first instar nymphs. As the eye grows more complex, the mechanisms to adapt to dark/light changes are also enhanced: eyes in dark conditions evidence less screening pigments, which would block light, than during the daytime, and changes in the width of the retinal layer to adapt to changes in available light are significantly more pronounced in adults. However, the larger size of the adult insects' eyes makes them more prone to radiation damage. This explains why fully grown individuals are mostly nocturnal. Lessened sensitivity to light in the newly emerged insects helps them to escape from the leaf litter wherein they are hatched and move upward into the illuminated foliage. Young stick insects are diurnal feeders and will move around freely, expanding their foraging range.