12 BRITISH ICHNEUMONS. [Ischnocerus. 



ISCHNOCERUS, Gravenhorst. 

 Gr. I.E. ii (1829), 949; Mitroboris, Holmgr. Sv. Ak. Handl., 1860, n. 10, p. 72. 



Head stout and broad but transverse, subbuccate and not narrower 

 posteriorly than the oval eyes ; frons with a central bifid, broad and 

 centrally canaliculate horn above the scrobes ; vertex broad, occiput 

 bordered ; epistoma subconvex and laterally obliquely canaliculate ; 

 clypeus discreted and deplanate, transverse and basally glabrous, with a 

 row of stout bristles at base and apex ; genal sulcus distinct, cheeks 

 elongate ; maxillary palpi ^'ery long, apically slender, with the two apical 

 joints subequal in length. Antennae very slender, filiform, a little longer 

 than the head and thorax, and obsoletely pilose throughout. Thorax 

 cylindrical and coarsely punctate ; mesonotum centrally depressed and 

 dull, longitudinally punctate ; notauli very distinct, sternauli wanting ; 

 metathorax apically obtusely produced laterally ; metanotal areae sharply 

 costate, apophyses very large and stout ; spiracles oval, oblique. Scutel- 

 lum triangular, deplanate and apically obtuse. Abdomen subpetiolate, 

 oblong, shining, convex, longer and about as broad as the thorax, of J 

 narrower ; basal segment bicarinate and margined throughout, with the 

 postpetiole gradually dilated ; segments two to six transaciculate and 

 apically glabrous ; the fourth ventral acutely prominent ; eighth of $ 

 exserted and conical ; terebra half length of body. Legs normal, femora 

 somewhat stout, claws curved and not pectinate. Wings a little 

 narrow, areolet wanting, fenestrae very broadly discreted. 



This genus is placed by Gravenhorst among the Crvptinac. Its name 

 appears to be founded upon the metathoracic apophyses and not upon the 

 frontal horn, which Gravenhorst entirely overlooked. Consequently we 

 find our British species placed under Xoridcs by Ratzeburg and a new 

 genus by Holmgren ; and it was not till i88o that the true synonymy was 

 established by Brischke. This was at once accepted, in MS., by Marshall 

 and the specimens in the British Museum show that Desvignes also 

 recognised Gravenhorst's genus. 



1. rusticus, Foiirc. 



Ichncitmon rusticus, Fourc. E.P. ii. 426. Ischnoccros rusticus, Gr. I.E. ii. 

 951 ; Tasch. Zeits. Ges. Nat. 1865, p. 139, i ? ; Voll. Schets. I. pi. i, fig. 23 ; 

 Brisch. Schr. Nat. Ges. Danz. 1880, p. 129. /. seticornis et I.filicornis, Kriech. 

 Corres. Zool. min. Ver. Reg., 1879, pp. 164-5, i ? . Xorides cornutus, Ratz. 

 Ichn. d. Forst. ii, 108, ? . Mitroboris cornuta, Holmgr. Sv. Ak. Hand!., 1860, 

 n. 10, p. 72, cT ? ; cf. Thorns, O.E. viii, 776. 



Strongly punctate, a little nitidulous and black, with the legs nearly entire- 

 ly bright red. Head with the clypeus semicircularly discreted, apically 

 subtrunctate and coarsely punctate, cheeks strongly and sparsely punctate ; 

 mandibles narrow, subdilated basally, externally subaciculate, convex and 

 obtusely bidentate at the apex with the upper tooth a little the longer ; 

 frons and vertex convex and broad, the latter much higher than the ocelli. 

 Antennae 35-jointed, slender subfiliform, black or nigrescent with the 

 flagellum ferrugineous beneath ; scape and flagellar joints elongate, the 

 latter a little nodulose apically. Thorax stout and cylindrical ; mesonotum 

 coarsely and, in the centre, sublongitudinally punctate ; metathorax 

 strongly and evenly punctate, with four stout, erect and apically obtuse 



