Phasmida (Stick- and Leaf-Insects)
Large, apterous or winged insects, frequently of elongate, cylindrical form, more rarely depressed and leaf-like. Mouthparts mandibulate. Prothorax short; mesoand metathorax usually elongate, the latter closely associated with 1st abdominal segment. Legs
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PHASMIDA (STICK- AND LEAF-INSEC TS) Large, apterous or winged insects, frequently of elongate, cylindrical form, more rarely depressed and leaf-like. Mouthparts mandibulate. Prothorax short; mesoand metathorax usually elongate, the latter closely associated with 1st abdominal segment. Legs similar to each other; coxae small and rather widely separated; tarsi almost always s-segmented. Fore wings, when present, usually small and with submarginal costa. Wing-pads do not undergo reversal during development. Ovipositor small and mostly concealed by enlarged 8th abdominal sternum. Male external genitalia variable and asymmetrical, concealed by 9th abdominal segment. Cerci short, unsegmented. Specialized auditory and stridulatory organs absent. Eggs deposited singly. Metamorphosis slight.
The Phasmida is a group of predominantly tropical insects (Gunther, 1953; Beier, 1957) remarkable for their close protective resemblance to the foliage or, more frequently, twigs, of the vegetation on which they occur and feed. Though formerly classified with the Dictyoptera as Cursorial Orthoptera, they show some similarities to the Saltatoria and because of their uncertain affinities they are here given separate ordinal status. For general accounts, see Beier (1968) and Chopard (1938; 1949). External Anatomy - In addition to the references cited below, the following papers deal with the anatomy of various members of this order: Heymons (1897), de Sinety (1901), Marshall and Severin (1906), Leuzinger eta/. (1926), Littig (1942) and Bauchhenss (1971). Two main types of bodily structure occur in the Phasmida: elongate, often apterous, cylindrical, rodlike forms which closely resemble twigs in colour and appearance (Fig. 260) and the less frequent depressed, leaf-like, winged species (Phylliidae) with lamellate expansions of the legs (Fig. 259). A few more thick-set forms, superficially similar to saltatorial Orthoptera, are also known and are probably more primitive than the plant-simulating species. The cuticle of the Phasmids is frequently beset with spines and other cuticular prominences. The head is prognathous with a well-developed frontoclypeal sulcus, but the ecdysial cleavage line and occipital sulcus are not evident and the transverse division of the clypeus is indistinct. The labrum is O. W. Richards et al., Imms’ General Textbook of Entomology © O. W. Richards and R. G. Davies 1977
PHASMIDA (STICK- AND LEAF-INSECTS)
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large and cleft apically and the tentorium (Hudson, 1945) is imperforate, with long anterior arms and a small body. Compound eyes are always present, but ocelli (usually 2) are found only in some of the winged species. The antennae vary considerably in length, being filiform or moniliform, with from 8 to over 100 segments. The biting mouthparts have strong mandibles and each maxilla possesses a 5-segmented palp, a 2-segmented galea and a lacinia which is spinose on its inner face. The labium is subdivided into prementum, mentum and submentum; the labial palps are 3-segmented, the paraglossae are well d
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