28 BRITISH ICHNEUMONS. [ Pertope 



PERIOPE, Haliday. 
Hal. Ann. Nat. Hist. 1839, p. 114; Monoplectron, Holmgr. Sv. Ak. Hand. 
1855, p. 81; Oligoplectron, Forst. Verh. pr. Rhein]. 1868, p. 161. 
Head transverse with the face subprotuberant; clypeus _ basally 
subarcuately impressed, but not discreted ; mandibles broad with stout 
teeth; eyes oblong and somew!.at emarginate next the scrobes; inter- 
antennal process not cristulate behind. Antennae subclavate, apically in- 
crassate, strongly attenuate basally, short and not as long as the body; 
scape not cylindrical. Thorax stout, gibbous and short ; mesosternal 
epicnemia interrupted above; metathorax with areae, of which the 
petiolar extends to its centre; costulae wanting; spiracles circular. 
Scutellum immarginate and subconvex. Abdomen subpetiolate, narrow, 
elongate-fusiform and in 9 apically a li.tle compressed ; spiracles of the 
basally constricted first segment a little beyond its centre; sixth ventral 
segment extending nearly to anus; terebra concealed. Legs short but 
not very stout; front and hind tibiae unicalcarate; claws pectinate. 
Areolet small, petiolate and obliquely subcircular ; lower basal nervure 
postfurcal ; nervellus antefurcal, suboblique and intercepted a little below 
the centre. 
At once known from all other Exochid genera by the unicalcarate hind 
tibiae and remarkable subclavate antennae. The genus was named 
Pertope in the first edition of Curtis’ Guide, Appendix, No. 538, though 
not there described. ‘There is but one palaearctic species of this genus, 
first described from Britain; but in 1897 Davis placed the Canadian 
Tryphon aethiops, Cress., in it. 
1. auscultator, Hal. 
Ichneumon impugnator, Schr. En. Insect. Austr, 368, ¢; F. B. ii. 300, 3 2; 
etc. ; cf. Gr. I. E. iii. 105 (?). Periope auscultator, Hal. Ann. Nat. Hist. 1839, 
p. 114, ¢: Thoms. Deut, Ent. Zeit. 1887, p. 198, ¢ ¢ .‘ Monoplectron zygaenator, 
Holmer. Sv. Ak. Handl. 1854, p. 81: Jib. cit. 1855, p. 306, pl. ix, fig.19; cf.l.c. 
p. 389 et Westw. Introd. ii. Synop. 57. 
A black and very strongly nitidulous species with the abdomen centrally, 
femora apically, tibiae and tarsi, red. Head black, shining and not con- 
stricted posteriorly ; frons apically impressed; face punctate and sub- 
prominent ; clypeus not discreted ; mandibles a little constricted apically, 
with the teeth subequal in length ; palpi infuscate. Antennae nigrescent 
and basally attenuate, of Q becoming ferrugineous beneath from the 
centre ; two basal flagellar joints elongate and nitidulous, the following 
pilose and quadrate, becoming transverse from the tenth, the apical joint 
conical and strongly obtuse ; flagellum of @ 23- and of ? 19-jointed. 
‘Thorax stout and black ; metathorax with the areola small and subtrans- 
verse, the two lateral areae triangular, and the supracoxal large and glab- 
rous ; spiracles circular. Scutellum glabrous, black, immarginate and 
subconvex, with its basal fovea not narrow. Abdomen strongly nitidulous, 
subcylindrical and deplanate with the Q anus subcompressed ; segments 
two and three red with their base infuscate ; basal segment bicarinate 
with the postpetiole subquadrate and spiracles slightly behind the centre ; 
the basally punctate second and the third more or less broadly red; and 
