​STICK-INSECT, the name given to certain orthopterous insects of the family Phasmidae, of extremely variable form and size, and deriving their name from a resemblance to the branches and twigs of the trees in which they live and feed. The resem- blance is produced by the great length and slenderness of the body and legs. Protection is afforded to some species, like Heteropteryx grayi from Borneo, by sharp thornlike spines. The anterior wings, when present, are always small; but the posterior wings are sometimes of large size and very beautifully coloured. The colouring, however, is only visible when the wings are expanded and in use. Many species are wingless at all ages. As in the leaf-insects, to which the stick-insects are closely allied, the egg-cases are very similar to seeds. Stick-insects ^re intolerant of cold, and attain their largest size and greatest pro- fusion of species in the tropics, one West African species, Palophus centaurus, reaching a length of 9 in. Species of small size are found in southern Europe, one belonging to the genus Bacillus advancing as far north as the middle of France.