vi ANTENNATA SYSTEMATIC REVIEW 439 



Legion I. Apterygota. 



Without wings. With rudiments of abdominal limbs, at least in the Thysanura. 

 Without metamorphosis. 



Order 1. Thysanura. 



With 10 abdominal segments and 2-3 jointed bristle- shaped appendages (cerci) on 

 the anal segment. Compound eyes and ocelli may be present or absent. Machilis, 

 Lepisma, Nicoletia, Campodea (Fig. 302, p. 444), lapyx. 



Order 2. Collembola. 



With 6 abdominal segments or fewer. Nearly always a springing fork at the end 

 of the hind-body. Without compound eyes. Occasionally with ocelli. Sminthurus, 

 Podura, Isotoma, Macrolomct. 



Legion II. Pterygota. 



With a pair of wings on both the 2d and 3d thoracic segments. There are 

 unwinged forms, which, however, are descended from winged ancestors. 



Order 1. Dermaptera (Forficulidse), Earwigs. 



Insects with gradual metamorphosis, and with biting mouth parts. The last 

 abdominal segment has unjointed appendages (cerci), which form a pincer. Fore- wings 

 short, changed into horny wing covers. Hind-wings large, delicate skinned, fan- 

 shaped, can be folded longitudinally and transversely. Paired genital apertures, of 

 which one may be rudimentary. Forficula, Labidura. 



Order 2. Orthoptera. 



Insects with gradual metamorphosis, with biting mouth parts ; with 2 pairs 

 of membranous or parchment-like wings, sometimes wanting. Fore-wing generally 

 shorter and more chitinous than the hind-wing. Variously shaped cerci on the hind 

 body. Sexual apertures unpaired. Embidce, Blattidce (cockroaches : Pcriplancta, 

 Blatta}. Mantidce (Mantis, praying insect). Phasmidce (stick or spectre insects, 

 Bacillus, Phasma, Phyllium}. Saltatoria, including the 3 families, Acridiidce 

 (grasshoppers : Acridium, (Edipoda, Mecostcthus, Stenobothrus, Tcttix, etc. ) ; Locustidce 

 (Locusta, Thamnotrizon, Platycleis, Decticus) ; and Gryllidce (Gryllus, Gryllotalpa, 

 Myrm ccophila). 



Order 3. Ephemeridse. 



Insects with incomplete metamorphosis. Mouth parts somewhat reduced, of 

 the biting type. Hind -wing small or wanting, fore -wing large, wings finely 

 membranous. Hind body with 3 (rarely 2) long cerci. Paired genital ducts, 

 emerging separately. Larvte apneustic, Thysanura-like, with tracheal gills, and with 

 biting mouth parts, live in water. Ephemera, Palingcnia, Chloe. 



Order 4. Odonata (Libellulidse). 



Insects with incomplete metamorphosis, and with biting mouth parts. Hind 

 body with 2 unjointed anal processes. Both pairs of wings are large, and glass-like, 

 with a rich network of veins. Thoracic legs moved forward. Larvae in water with 

 various sorts of tracheal gills, apneustic. Libcllula, ^Jschna, Caloptcryx, Agrion, etc. 



