12 BRITISH ICHNEUMONS. [Aperileptus 



APERILEPTUS, Forster. 



Forst. Verb. pr. Rheinl. 1868, p. 170 (?) ; Forst. I.e. 1871, p. 75; Thorns. O.E. 

 xii. 1297. 



Head small and shorll}- triangular with the vertex posteriorly deeply 

 emarginate, impressed behind ocelli and transcostate before occiput ; 

 eyes not pilose; face parallel-sided and slightly convex; clypeus broad, 

 discreted and subconve.x', cheeks subelongatc; mandibles with the aciun- 

 inate upper tooth the longer. Antennae slender, filiform and elongate 

 with 1 8 to 23 joints, and erect but not verticillate pilosity; t]agellar joints 

 elongate and cylindrical with first longer than second. Mesonotum 

 glabrous and nitidulous, with no notauli, and scutellar fovea broad and 

 deep; metathorax convex, smooth and shining with no areae, though 

 with the petiolar sometimes apically indicated. Scutellum convex and 

 margined to its centre. Abdomen subsessile ; basal segment gradually 

 explanate, as long as apically broad and laterally substriate ; the following 

 segments smooth and shining, with second of 9 niuch broader than long ; 

 terebra long, with its sheaths elongately pilose. Legs somewhat stout, 

 with calcaria not short, and claws subelongate. Stigma not narrow ; 

 areolet entire and obliquely quadrate; parallel nervure emitted from centre 

 of brachial cell ; basal nervure continuous, and nervellus not geniculate. 



This genus is at once known by the smooth and nitidulous metathorax 

 with no areae, and by the subsessile abdomen. 



1. albipalpus, Grav. 



Plectiscus albipalpus, Gr. I.E. ii. 986, <J ? ; cf. Hal. Ann. Nat. Hist. 1839, 



p. 116 e^ Blanchard, Hist. Ins. iii. 316. Aperileptus albipalpus, Forst. Verb. pr. 



Rheinl. 1871, pp. 77, 79; Tboms. O.E. xii, 1298,,? ?; Brisch. Schr. Nat. Ges. 

 Danz. 1880, p. 200, ? . 



Head with the mouth stramineous, and V face testaceous with an 

 infuscate mark or nigresent with sometimes obsolete lateral marks below 

 the scrobes dull stramineous. Antennae as long as body and in ^ sub- 

 denticulate; three or four basal joints stramineous beneath. Thorax 

 gibbous, of 9 with the lateral sutures sometimes substramineous. Abdo- 

 men of (J with second and third segments discally testaceous ; of 9 as 

 long and as broad as head and thorax, oblong or ovate, with basal seg- 

 ment sometimes apically stramineous ; second segment black with its 

 disc or apex testaceous, or testaceous with only its base black ; third 

 discally or basally testaceous; terebra as long as abdomen. Legs stra- 

 mineous and normally stout ; hind ones with tibial apices and the tarsi 

 subinfuscate. Wmgs ample and hyaline with the stigma and radius 

 piceous, tegulae and radices whitish or stramineous, and the obliquely 

 transverse areolet subpetiolate. Length, 4-5 mm. 



I here give Gravenhorst's original description of this species, which 

 Forster subsequently divided into over thirty, with additions from Thom- 

 son and Strobl. Some of the latter may be good, but only the typical 

 one is recorded from Britain and that alone I recognise. In its most 

 restricted sense A. albipalpus may be known by possessing 20-jointed 

 antennae, vertical nervellus, prominent petiolar spiracles, terebra about 

 length of abdomen, sternum black, face ferrugineous with only clypeus, 

 clypeal region and antennal base whitish flavous, and the legs immaculate 

 testaceous. 



