Acaenitus.] BRITISH ICHNEUMONS. 259 



ACAENITUS, Latreille. 

 Latr. Gen. Crust, et Ins. iv. (1809), 9. 



Head transverse, subbuccate and not narrowed behind the oval and 

 entire eyes ; clypeus short and transverse, deeply and semicircularly dis- 

 creted from the square face, with the apical margin subtruncate and cen- 

 trally reflexed ; mandibles longitudinally striate ; apically bifid with the 

 upper tooth the more obtuse ; ligula exserted ; antennal scrobes deeply 

 impressed ; genal costa inflexed. Antennae filiform, as long as or rather 

 longer than half the body. Thorax stout and strongly convex, with no- 

 tauli very distinct ; mesosternum short, with indications of lateral sulci ; 

 metathorax short and rugose with indistinct areae, spiracles large and 

 elliptic, of J sublinear. Scutellum apically elevated and obtusely rounded, 

 with erect pilosity. Abdomen smooth, as long as head and thorax, some- 

 what narrower and subcompressed apicallv, subsessile, convex and oblong, 

 of (^ more constricted and longer than in 9 ! basal segment smooth and 

 subcanaliculate, gradually dilated apicallv, narrower in (^ ; sixth of 9 

 ventrally concave and elongately acuminate ; terebra from about half to 

 fully length of body. Hind legs elongate and incrassate, with the tarsal 

 claws large, curved and not pectinate ; front tibiae unicalcarious. Wings 

 with no areolet ; the upper pair with basal nervure perpendicular and not 

 curved, fenestrae large and nearly confluent ; lower ones with the first 

 recurrent postfurcal. 



Gravenhorst calls attention to the relationship of this genus with Li's- 

 sonota, Colfoceii/nis, Aro/es and Collvria. It is, however, abundantly dis- 

 tinct from any of these and probably most closely related to Lampnmota, 

 though the superficial resemblance to the Braconidous genus Helcon is, as 

 remarked by Haliday (f^nt. Mag. 1836, p. 143), curiouslv striking. 



Table of Species. 



(2). I. Abdomen immaculate black; terebra 



shorter than abdomen i. .\R.\roR, Rossi, 



(i). 2. Abdomen white-banded, centrally red; 



terebra longer than abdomen 2. DUIUTATOR, PcDiz. 



1. arator, Ros^i. 



Ichneumon arator, Rossi, F.I-:. ii. 49. Acaeititcs arator, Gr. I.E. iii. 813 ; 

 Holmgr. Sv. Ak. Hand!. 1860, n. 10, p. 8; Tasch. Zeits. Ges. Nat 186.S. p. 298; 

 Veil. Schets. I, pi. iii, {. 5, j ? . 



Black and shining. Mead with short, black pilositv ; palpi infuscate, 

 ligula stramineous; clypeus strongly bisinuate on either side; face strongly 

 longitudinally impressed on either side below the scrobes, which reach 

 the vertex and enclose a distinct frontal carina. Antennae about half 

 length of the body, of J very stout, strongly obtuse at apex and hardly 



S2 



