20 BRITISH ICHNEUMONS. {Dicolus 



basal area obsolete or wanting, petiolar short and distinct; sternum 

 always pale. Scutellum apically strongly compressed on either side. 

 Abdomen elongate, of $ narrow and of 9 explanate towards the anus ; 

 basal segment sublinear and hardly broader apically, with subcentral 

 spiracles; terebra not exserted. Legs long and slender, with apical third 

 of hind tibiae often constricted. Areolet always wanting, with distinct 

 areolar nervure; nervellus geniculate. 



The constriction of the metathorax is characteristic of this genus and 

 unique among Ichneumonidae. 



Table of Species. 



(4). I. Apical third of hind tibiae broadly 

 emarginate ; calcaria somewhat 

 long. 



(3). 2. Frontal orbits apically white; face 



flavidous; antennae 34-jointed . . i. PECTORALIS, i^Jrj-/. 



(2). 3. Frontal orbits not white ; face piceous ; 



antennae 31-jointed .. .. 2. SUBTILIVENTRIS, i^Jrj-/. 



(i). 4. Apical third of hind tibiae not emar- 

 ginate; calcaria somewhat short 3. insectator, i^(yrj-/. 



1. pectoralis, Fdrsf. 



Dicolus pectoralis, Forst. Verb. pr. Rheinl. 1871, p. 97; Thorns. O.E. xii, 

 1315, 3 ? . 



A black, piceous, flavous and white-marked species. Frontal orbits in 

 both sexes shortly pale; face testaceous. Antennae 33 or 34-jointed in 

 both sexes. Metathorax finely alutaceous and not scabriculous, with the 

 central frenal area wanting, the costulae wanting, but the transverse 

 carina entire and rendering the petiolar area determinate; sternum pale. 

 Hind tibiae strongly constricted at their apical third, with somewhat 

 elongate calcaria. Head with vertex narrow. Length, 3-4 mm. 



Bridgman considered this species "very distinct and easily recognised," 

 though the above is the total description at present available. 



He says (Trans. P^nt. Soc. 1883, p. i6g) that it "is added to our list on 

 the strength of a female which was sent to me by the Rev. T. A. IMar- 

 shall," without locality. Bignell, however, confirms it as British by 

 recording it from Horrabridge in Devon on 4th July; and I also possess 

 a female labelled Teddington, October, 1891, from de la Garde. 



2. subtiliventris, Forst. 



Dicolus subfilivciifris, Forst. Verh, pr. Rheinl. 1S71, p. 97; Bridg. Trans. Ent. 

 Soc. 1887, p. MS. Thorns. O.E. xii. 1315, ? . 



A black species, with pale markings and the frontal orbits immaculate. 

 Head shining and very finely punctate, posteriorly constricted; clypeus 

 small, semicircular and distinctly discreted from the partly piceous face, 

 which is centrally prominent; mouth and clypeus fulvous, palpi whitish. 

 Antennae rufescent and paler beneath, a little longer than body, with 

 thirty-one densely and elongately pubescent joints. Thorax discally 



