450 [December, 



SYNOPSIS OF THE BEITISH ORTEOPTERA. 



BY ELAND SHAW, F.E.S. 



{Continued, from page 421). 



iv.-PACHYTYLUS, Fieber. 

 In this genus the species are much larger. Head, with the irons, 

 joining the vertex at an obtuse angle ; frons not sulcate in the middle, 

 but sub-convex, with a slight depression around the ocellus. Eoveolse 

 of the vertex small, triangular, with their bases just anterior to the eyes. 

 Pronotum with a more or less elevated median ridge, no lateral ridges ; 

 posterior margin more sharply angled than in Stenobothrus and Gom- 

 pJiocerus. Elytra with the ulnar area wide ; anterior ulnar vein at the 

 extremity of the discoidal cell bent downwards somewhat abruptly, 

 beyond this running very straight and parallel with the posterior radial 

 vein, and enclosing with the latter a narrow area containing an 

 accessory vein. Posterior femora with the superior ridge sharp, with 

 a few serrations. First segment of the abdomen with the external 

 auditory orifice partly open. 



Table of Species. 



1 (2) Pronotum with the anterior margin less produced, median ridge slightly 



elevated. $ and ? of equal size 1. migratorius, Linne. 



2 (1) Pronotum with the anterior margin produced further forwards, median 



ridge considerably elevated. <J much smaller than the ? ... 



2. cinerascens, Fab. 



1. — Pachtttlus migratokicis, Linne. 



Qryllus (Locust a) migratorius, Linne, Syst. Nat., ed. x, p. 432, ed. xii, 

 i, 2, p. 700 ; Donovan, Brit. Ins., viii, 49, pi. 270. 



Lo. migratoria, Steph., Mandib., vi, p. 20. 



Pacliytylus migratorius, Pisch., Orth. Eur., p. 393, tab. xviii, figs. 12, 

 12« ; Brunner, Prod, der Eur. Orth., p. 171. 



General colour yellowish or greenish-grey, livid, or partly paler green. Head 

 with the vertex between the eyes flat, sloping forwards and downwards, with a 

 central median ridge, which anteriorly meets a bluntly angled transverse ridge, sepa- 

 rating the vertex from the frons. Behind the eyes is a curved fuscous streak on 

 either side. Frons with the ridges on either side parallel, fuscous or dark greenish- 

 blue. Mandibles blackish-blue. Pronotum pale green, sometimes with a fuscous 

 streak on either side, with the anterior margin slightly angled in the middle ; median 

 ridge not much elevated, nearly straight when seen from the side, slightly notched 

 by the cross furrow. The pronotum is considerably broader posteriorly than an- 

 teriorly, anterior half compressed, spreading out behind suddenly, with a well marked 



