HEMIMETABOLIC INSECTS. 597 



England, regarded by Mr Butler as being a Butterfly, is considered 

 by Mr Scudder as truly a Cicada. 



Order III. Orthoptera. — In this order the mouth is mastica- 

 tory ; the wings are four, sometimes wanting, the a?ite?'ior pair mostly 

 smaller than the posterior and of a semi-coriaceous or leathery consist- 

 ence. The poste?'ior wings, when not in use, are plaited longitudinally 

 like a fan or may be transversely folded. The interspaces between the 

 nervures are filled with transverse reticulations, a?id the anal area of 

 the wing is of large size. The antenna? are usually filiform, and the 

 females are usually provided with an ovipositor. 



The earliest types of the Orthoptera appear in the Trias, where 

 the order is represented by several forms of Cockroaches. In the 

 Jurassic rocks are found forms belonging to the families of the Ear- 

 wigs {Baseopsis, of the Lias), the Locusts (Gryllacris and Locustd), 

 and the Crickets (Gryllus), while the Grasshoppers (Acrididaz) are 

 doubtfully represented in deposits of Mesozoic age. All the pre- 

 ceding families continue to be well represented in the Tertiary 

 rocks, and in deposits of this age appear also forms belonging to 

 the families of the Mantidai and Phasmidaz. 



Order IV. Neuroptera. — Mouth usually masticatory ; wings 

 four in number, all membranous, generally nea?'ly equal in size, 

 traversed by numerous delicate nervures, which have a longitudinal 

 and transverse direction, thus giving them a reticulated, lace-like 

 aspect (fig. 448). Jfetamorphosis in some groups incomplete, in other 

 groups complete. The larva active, hexapod, the pupa active or 

 quiescent. 



The insects included in the order Neuroptera differ so widely 

 in their characters, habits, and metamorphoses that they may be 

 divided into the three primary groups of the Pseudoneuroptera, the 

 Neuroptera vera, and the Trichoptera, of which the first consti- 

 tutes a transitional group between the typical Neuroptera and the 

 Orthoptera. 



The Pseudoneuroptera are characterised by their incomplete meta- 

 morphosis, the larvae being commonly inhabitants of water, and the 

 pupae being active. Of the groups included in this section of the 

 order, the Termites or " White Ants " are represented in rocks as 

 old as the Lias, and abounded in Tertiary times. The May-flies 

 (Ephemeridce) and the Dragon-flies (Libellulidaz) likewise commenced 

 their existence in the Jurassic rocks, and have many Tertiary repre- 

 sentatives. Beautifully preserved examples of the Dragon-flies have 

 been yielded by the fine-grained Lithographic Slates of Solenhofen 

 (fig. 448), while still older forms have been recognised in the Lias. 

 Lastly, the family of the Pei-lida*, including the recent " Stone-flies," 

 is represented in the Eocene Tertiary. 



The group of the Neuroptera vera includes those members of 



