Acroricnus.] BRITISH ICHNEUMONS. 3^5 



Our single species has hitherto been referred to the genus Linoceras, 

 which name is now considered to have been preoccupied. Forster (Verb, 

 pr. Rheinl. 1868, p. 186) termed it Xenodocon, and Kriechbaumer (Ent. 

 Nachr. 1878, p. 22 ; cf. also p. 251 et 1879, P- 3) further involved the 

 synonymy by incorrectly referring it to Ospryncholus, Spin. (Guer. Mag. 

 Zool. 1841, no. 75). 



I. macrobatus, Grav. 



Cryptus inairohatus, Gr I. E. ii. 440 ; Zett. I. L. 368, i ? . fJuoceras inacrohatiis, 

 Tasch. Zeits. Ges. Nal. 1865, p. 106 ; Voll. I'inac. pi. vi. f. i ; Thorns. O. E. v. 475, 

 (J 9 ; </ lily- (it- xxi. 2347 et Brisch. Schr. Ges. Danz. 1879, p. 331. Acroricnus 

 Schauinii, Ralz. Ichn. d. Forst. iii. 92, i (fig.). Macrobatus clavator, Holmgr. Sv. Ak. 

 Handl. 1854, p. 50.^ 



Head with black pubescence ; of 6 with face and mouth, except apices 

 or whole of mandibles, flavous ; of 9 sometimes entirely black, but 

 generally with internal orbits very narrowly flavous. Antennae shorter 

 than body ; more or less rufescent beneath ; centrally flavous-banded in 

 both sexes ; $ with scape always pale beneath. Thorax with black pubes- 

 cence, immaculate ; metathorax strongly rugose, with dark pilosity and 

 both transverse costae strong, the apical being centrally obsolete in the ? . 

 Scutellum black, punctate, with long black hairs and glabrous interstices. 

 Abdomen broadest behind centre, black ; apex of first segment and centre 

 or sides of second usually castaneous, at least in <^ , which has the anus 

 sub-compressed ; petiole convex, extremely finely punctate and nitidulous ; 

 terebra slightly recurved, very nearly as long as abdomen, black, with long 

 pilosity and red spicula. Legs pale red : coxae, trochanters and apices of 

 the strongly curved hind tibiae, black ; front coxae, and often their femora 

 and tibiae, of S flavous-marked beneath ; all the tarsi of the S , and hind 

 ones of 9 , stramineous-white, excepting the onychii and base of the meta- 

 tarsi. Wings hyaline or distinctly clouded ; radix ferrugineous, tegulae 

 dark. Length, 12 mm. 



The extent of alar infumescence is extremely variable. 



This species would appear to have been considered very rare in Britain 

 until recent years ; it was first recorded by Desvignes, but Bridg.-Fitch 

 (Entom. 1883, p. 37), had seen only one specimen, taken at Venlnor by 

 Pascoe, in July, 1867. I have examined examples of both sexes, found 

 by Hamm at Bovey Tracey, in August, 1899, 1900 and 1902 ; and in 

 August, 1 90 1, myself discovered the species, together with Eumenes 

 coarcta/n, in some numbers at Matley Bog in the New Forest, where they 

 were attracted freely to the fltnvers of Angelica sy/vestris, upon which both 

 sexes would alight very gently and circumspectly, after hovering for a 

 moment or two before settling ; Adams took it at Lyndhurst, in the same 

 vicinity, in 1902. With us it is probably confined to the southern 

 counties, since I have never met with it in Suffolk. 



Its range extends throughout Europe ; Herr draff has bred it in 

 Germany from Euftienes coarctata at the end of May, and Schmiedeknecht 

 records it from Emnenes pomiformis, while, in France, Lal)oulbene in- 

 stances Eumenes sp. and Osmia adtinca as its hosts. 



1 Ophion clavator. Fab., suggested as a synonym of this species by Thomson, is Exciastcs cinclipcs, 

 Retz. (cj. Mori. E.M.M. 1903, p. 159). 



