46 BRITISH ICHNEUMONS. [PctMons. 



There can be no doubt that Desvignes' male appertains to this genus 

 since his single specimen, which 1 have examined, still exists in the 

 British Museum collection ; it was " taken by F. Walker, Esq.," presum- 

 ably in Britain, though such details of distribution hardly appear to have 

 entered the heads of the older authors. 



2. mediator, Fab. 



Pivtpla mediator, Fab. Piez. 117, ? . Ephialtes mediator, Gr. I.E. iii. 250; 

 Zett. I.L. 374; Ratz. Ichn. d. Forst. ii. 100; Tasch. Zeits. Ges. Nat. 1863, p. 256, 

 cT ? . Perithous mediator, Holmgr. Sv. Ak. Handl, 1860, n. 10, p. 15, <? ? ; cf. 

 Thorns. O.K. viii. 744. Piiiipla (Ephialtes) senator, Hal. Ann. Nat. Hist. 1839, 

 p. 116, ? . (?) Ichneumon sciirra, Panz., F. G. xcii. 6, ? . 



Head with the frontal orbits and mouth parts, except the apices of the 

 mandibles, whitish ; the very distinctly emarginate clypeus and whole face 

 white in ^ , latter with the internal and vertical orbits onlv and the former 

 sometimes with two dots white in 9 • Antennae shorter than the body ; 

 infuscate and apicallv subferrugineous above, beneath testaceous with the 

 two or four basal joints paler. Thorax black with the mesothorax red ; 

 prothorax immaculate ; a line before and beneath the radix, a dot beneath 

 the hind wings, and a sometimes red-margined transverse line or sinuate 

 mark in the petiolar area, fla\'idous-white ; metathorax discally punctate 

 and shining. Scutellum red with its apex, sometimes its sides, and the 

 postscutellum whitish. Abdomen shining, about thrice longer than 

 thorax and broadest behind the centre ; narrower in (J ; basal segment 

 nearly parallel-sided, subcanaliculate and rarely immaculate ; the seven 

 ba.sal segments apically discally and with the apical angles white ; terebra 

 somewhat longer than the body, black with the spicula red ; apical ventral 

 segment of J obtusely rounded. Legs pale flavidous with the posterior 

 of 9 > and more or less of the (J coxae and femora, red ; hind tarsi, not 

 distinctly dark -banded, their tibiae at apex and before base infuscate. 

 Wings flavescent or hyaline ; stigma, radix and tegulae piceous or strami- 

 neous ; areolet sessile, subirregular or nearly triangular. Length, 6^ — 

 14 mm. 



This species may be known from P. 7<arius by the shape of the internal 

 cubital nervure, which is centrally distinctly angled and emits a distinct 

 nervelet, whereas in the latter it is evenh' curved throughout with, espec- 

 ially in 9 ) hardly a trace of a nervelet. 



Haliday {I.e.) shortly describes/*, ^rw^z/flr; — Internal orbits white; meso- 

 thorax red, with white markings; segments white-margined, the inter- 

 mediate subtransverse ; terebra as long as body; legs red; length, 4 lines. 

 He adds that it is " intermediate between P. divinator and P. mediator, 

 resembling the first by its shorter figure and the form of the radial areolet, 

 the latter in the length of the oviscapt;" but nobody has seen anything 

 like it, and his description is too short and bears no features which do not 

 equally well apply to P. mediator. 



This is much the commonest species of the genus in Britain, and may 

 be frequently swept among long herbage in June and July, as well as bred 

 from bramble sticks. I have met with no direct instances of its parasitism 

 upon Aculeata, although I saw a female investigating holes in a dead 

 willow trunk tenanted by Ptmphjrdon lugnbris in my garden, at Monks' 

 Soham, in September, IQ07; on the contrary, it is said that Bouch6 bred 



